Triazole derivatives and their use as PDE4 activators

ABSTRACT

Compounds of Formula (I), which are activators of long form cyclic nucleotide phosphodiesterase-4 (PDE4) enzymes, are provided. Methods and uses of these compounds for the treatment or prevention of disorders requiring a reduction of second messenger responses mediated by cyclic 3′,5′-adenosine monophosphate (cAMP) are also described.

This application is a national phase entry pursuant to 35 U.S.C. § 371of International Application No. PCT/GB2016/050766, filed Mar. 18, 2016,which claims the benefit of GB Application No. 1504763.2, filed Mar. 20,2015, each of which is incorporated by reference herein in its entiretyfor any purpose.

FIELD OF THE INVENTION

The present invention relates to compounds of Formula I or Formula II,which are activators of long form cyclic nucleotide phosphodiesterase-4(PDE4) enzymes (isoforms) and to therapies using these activators. Inparticular, the invention relates to these activator compounds for usein a method for the treatment or prevention of disorders requiring areduction of second messenger responses mediated by cyclic3′,5′-adenosine monophosphate (cAMP).

BACKGROUND TO THE INVENTION

Cyclic 3′,5′-adenosine monophosphate—“cAMP”—is a critical intracellularbiochemical messenger that is involved in the transduction of thecellular effects of a variety of hormones, neurotransmitters, and otherextracellular biological factors in most animal and human cells. Theintracellular concentration of cAMP is controlled by the relativebalance between its rate of production and degradation. cAMP isgenerated by biosynthetic enzymes of the adenylyl cyclase superfamilyand degraded by members of the cyclic nucleotide phosphodiesterase (PDE)superfamily. Certain members of the PDE superfamily, such as PDE4,specifically degrade cAMP, while others either specifically degradecyclic guanosine monophosphate (cGMP) or degrade both cAMP and cGMP.PDE4 enzymes inactivate cAMP, thereby terminating its signalling, byhydrolysing cAMP to 5′-AMP (Lugnier, C. Pharmacol Ther. 109: 366-398,2006).

Four PDE4 genes (PDE4A, PDE4B, PDE4C and PDE4D) have been identified,each of which encodes a number of different enzyme isoforms through theuse of alternative promoters and mRNA splicing. On the basis of theirprimary structures, the catalytically active PDE4 splice variants can beclassified as “long”, “short” or “super-short” forms (Houslay, M. D.Prog Nucleic Acid Res Mol Biol. 69: 249-315, 2001). A “dead short” formalso exists, which is not catalytically active (Houslay, M. D., Baillie,G. S. and Maurice, D. H. Circ Res. 100: 950-66, 2007). PDE4 long formshave two regulatory regions, called upstream conserved regions 1 and 2(UCR1 and UCR2), located between their isoform-specific N-terminalportion and the catalytic domain. The UCR1 domain is absent in shortforms, whereas the super-short forms not only lack UCR1, but also have atruncated UCR2 domain (Houslay, M. D., Schafer, P. and Zhang, K. DrugDiscovery Today 10: 1503-1519, 2005).

PDE4 long forms, but not short forms, associate into dimers within cells(Richter, W and Conti, M. J. Biol. Chem. 277: 40212-40221, 2002; Bolger,G. B. et al., Cell. Signal. 27: 756-769, 2015). A proposed negativeallosteric modulation of PDE4 long forms by small molecules has beenreported (Burgin A. B. et al., Nat. Biotechnol. 28: 63-70, 2010; GurneyM. E. et al., Handb. Exp. Pharmacol. 204: 167-192, 2011).

It is known in the art that PDE4 long forms may be activated byendogenous cellular mechanisms, such as phosphorylation (MacKenzie, S.J. et al., Br. J. Pharmacol. 136: 421-433, 2002) and phosphatidic acid(Grange et al., J. Biol. Chem. 275: 33379-33387, 2000). Activation ofPDE4 long forms by ectopic expression of a 57 amino acid protein (called‘UCR1C’) whose precise sequence reflects part of that of the upstreamconserved region 1 of PDE4D (‘UCR1C’ sequence reflects that of aminoacids 80-136 while UCR is amino acids 17-136: numbering based on thePDE4D3 long isoform) has recently been reported (Wang, L. et al., Cell.Signal. 27: 908-922, 2015: “UCR1C is a novel activator ofphosphodiesterase 4 (PDE4) long isoforms and attenuates cardiomyocytehypertrophy”). The authors hypothesised that PDE4 activation might beused as a potential therapeutic strategy for preventing cardiachypertrophy.

Small molecules that act as activators of PDE4 long forms have notpreviously been disclosed. Small molecule activators would be desirablefor a number of reasons, including ease of manufacture and formulationand improved pharmacokinetic properties.

It is amongst the objects of the present invention to provide smallmolecule activators of at least one of the long forms of PDE4 of FormulaI or Formula II for use in a method of therapy, as well as specificdisease treatment or prevention.

SUMMARY OF THE INVENTION

In a first aspect of the invention, there is provided a compound ofFormula 1:

Wherein

-   R¹ is H, (C1-4) alkyl or (C1-4)alkyloxy, the (C1-4)alkyl and    (C1-4)alkyloxy groups being optionally substituted with 1 to 3    fluoros;-   R² and R⁶ are independently selected from H, (C1-4)alkyl,    (C1-4)alkyloxy, —CN and halogen, the (C1-4)alkyl and (C1-4)alkyloxy    groups being optionally substituted with 1 to 3 fluoros;-   R³, R⁴ and R⁵ are independently selected from H, (C1-4)alkyl,    (C1-4)alkyloxy, (C1-4)alkylsulfonyl, C(O)—NR¹⁶R¹⁷, C(O)—OR¹⁶,    S(O)₂—NR¹⁶R¹⁷, —CN and halogen, the (C1-4)alkyl and (C1-4)alkyloxy    groups being optionally substituted with 1 to 3 fluoros;-   R⁷, R⁸, R¹⁰ and R¹¹ are independently selected from H and F;-   R⁹ is selected from H, (C1-4)alkyl, (C1-4)alkyloxy,    (C1-4)alkylsulfonyl, C(O)—NR¹⁶R¹⁷, C(O)—OR¹⁶, S(O)₂—NR¹⁶R¹⁷, CN and    halogen, the (C1-4)alkyl and (C1-4)alkyloxy groups being optionally    substituted with 1 to 3 fluoros;-   R¹², R¹³, R¹⁴ and R¹⁵ are independently selected from H and    (C1-4)alkyl;-   each R¹⁶ and R¹⁷, when present, is independently selected from H and    (C1-4)alkyl;-   or a pharmaceutically acceptable salt thereof.

The triazole derivative compounds of Formula 1 are shown in the Examplesto activate PDE4 long form enzymes, and to provide therapeuticallyuseful effects on cells.

In one embodiment, the present invention provides a compound of Formula1 for use in therapy. In another embodiment, the therapy is thetreatment or prevention of a disease or disorder mediated by excessiveintracellular cAMP signalling. In these diseases, a reduction of secondmessenger responses mediated by cyclic 3′,5′-adenosine monophosphate(cAMP) should provide a therapeutic benefit. Also provided is a methodof treating or preventing a disease or disorder mediated by excessiveintracellular cAMP signalling, comprising the step of administering aneffective amount of a compound of Formula 1 to a patient in needthereof. Also provided is the use of a compound of Formula 1 in themanufacture of a medicament for treating or preventing a disease ordisorder mediated by excessive intracellular cAMP signalling.

The invention also provides a compound of Formula 2, for use in therapy:

wherein

-   R¹ is H, (C1-6)alkyl or (C3-7)cycloalkyl, the (C1-6)alkyl and    (C3-7)cycloalkyl groups being optionally substituted with 1 to 3    substituents selected from OH, (C1-4)alkyloxy, (C1-4)alkylsulfonyl,    C(O)—NR¹⁶R¹⁷, C(O)—OR¹⁶, S(O)₂—NR¹⁶R¹⁷, CN and halogen;-   R² and R⁶ are independently selected from H, (C1-4)alkyl,    (C1-4)alkyloxy, —CN and halogen, the (C1-4)alkyl and (C1-4)alkyloxy    groups being optionally substituted with 1 to 3 fluoros;-   R³, R⁴ and R⁵ are independently selected from H, (C1-4)alkyl,    (C1-4)alkyloxy, (C1-4)alkylsulfonyl, C(O)—NR¹⁶R¹⁷, C(O)—OR¹⁸,    S(O)₂—NR¹⁶R¹⁷, —CN and halogen, the (C1-4)alkyl and (C1-4)alkyloxy    groups being optionally substituted with 1 to 3 fluoros;-   R⁷, R⁸, R¹⁰ and R¹¹ are independently selected from H and F;-   R⁹ is selected from H, (C1-4)alkyl, (C1-4)alkyloxy,    (C1-4)alkylsulfonyl, C(O)—NR¹⁶R¹⁷, C(O)—OR¹⁶, S(O)₂—NR¹⁶R¹⁷, —CN and    halogen, the (C1-4)alkyl and (C1-4)alkyloxy groups being optionally    substituted with 1 to 3 fluoros;-   R¹², R¹³, R¹⁴ and R¹⁵ are independently selected from H and    (C1-4)alkyl;-   each R¹⁶ and R¹⁷, when present, is independently selected from H and    (C1-4)alkyl;-   or a pharmaceutically acceptable salt thereof.

Compounds of Formula 2 are shown in the Examples to activate a long formcyclic phosphodiesterase-4 (PDE4) enzyme and to provide therapeuticallyuseful effects on cells.

A compound of Formula 1 or Formula 2 can be provided in a pharmaceuticalcomposition comprising a pharmaceutically acceptable excipient.

In certain embodiments of the foregoing aspects, the compounds of theinvention are provided for the treatment or prevention of a conditionselected from hyperthyroidism, Jansens's metaphyseal chondrodysplasia,hyperparathyroidism, familial male-limited precocious puberty, pituitaryadenomas, Cushing's disease, polycystic kidney disease, polycystic liverdisease, McCune-Albright syndrome, cholera, whooping cough, anthrax,tuberculosis, HIV, AIDS, Common Variable Immunodeficiency (CVID),melanoma, pancreatic cancer, leukaemia, prostate cancer, adrenocorticaltumours, testicular cancer, primary pigmented nodular adrenocorticaldiseases (PPNAD), Carney Complex, autosomal dominant polycystic kidneydisease (ADPKD), autosomal recessive polycystic kidney disease (ARPKD),maturity onset diabetes of young type 5 (MODY5), or cardiac hypertrophy.

In a further aspect, the invention provides a method of preparing acompound of Formula 1 or a pharmaceutically acceptable salt thereof,comprising the step of reacting a compound of Formula 1A

with a compound of Formula 1B

wherein R1-R15 are defined for Formula 1 above.

The invention also provides a method of preparing a compound of Formula1 or a pharmaceutically acceptable salt thereof, comprising the step ofreacting a compound of Formula 1C

with a compound of Formula 1D

wherein R1-R15 are defined for Formula 1 above.

Intermediates of Formula 1A and 1C are also provided by the invention.

In yet another aspect, the invention provides a method of identifying acompound able to activate a long form PDE4 enzyme, comprising the stepsof:

-   -   a. contacting a long form PDE4 enzyme with a candidate compound;    -   b. determining whether the candidate compound activates the        enzyme to at least the same level as a compound of Formula 1 or        Formula 2.

The method may be performed according to one of the methods in theExamples. In one embodiment, the method further comprises the prior orsubsequent step of determining whether the candidate compound activatesa short or super-short PDE4 enzyme. A compound that activates a longform PDE4 and does not activate a short or super-short form PDE4 isselective for long form PDE4. One or more of the compounds exemplifiedherein may be used as the reference or control.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows activation of PDE4D5, a long form of PDE4, by Examples A,B, D and L;

FIG. 2 shows activation of PDE4A4, another long form of PDE4, by ExampleA;

FIG. 3 shows activation of PDE4B1, another long form of PDE4, by ExampleA;

FIG. 4 shows a lack of activation of PDE4B2, a short form of PDE4, byExamples A, B, D and L using the method of Experiment 1, demonstratingselectivity for activation of PDE4 long forms over this PDE4 short form;

FIG. 5 shows a reduction in intracellular cAMP levels in HEK293 cellstreated with a PDE4 long form activator (10 μM)—Example A—for 10 minprior to forskolin (F) (10 μM) for 2 min;

FIG. 6 shows a reduction in intracellular cAMP levels in MDCK cellstreated with PDE4 long form activators (10 μM)—Examples A, C and D—for10 min prior to forskolin (F) (10 μM) for 2 min;

FIG. 7 shows inhibition of in vitro cyst formation in MDCK cells treatedwith a PDE4 long form activator—Example A—using the method described inExperiment 3, with addition of the specified concentrations of the testcompounds every 2 days from day 0 to day 20;

FIG. 8 shows a reversal of in vitro cyst formation in MDCK cells treatedwith a PDE4 long form activator—Example A—using the method described inExperiment 4, with addition of the specified concentrations of the testcompounds every 2 days from day 10 to day 20;

FIG. 9 shows (normalised cell index at 72 hours) that a PDE4 long formactivator—Example A—inhibits the proliferation of androgen-sensitive(AS) LNCaP human prostate cancer cells in a concentration dependentmanner, using the method described in Experiment 5;

FIG. 10 shows (normalised cell index at 72 hours) that, using the methoddescribed in Experiment 5, a PDE4 long form activator—Example A—inhibitsthe proliferation of androgen-insensitive (AI) LNCaP human prostatecancer cells in a concentration dependent manner;

FIG. 11 shows the mouse pharmacokinetic profile of Example A, determinedby whole blood analysis at defined time points after i.v. and p.o.administration to male C57 mice; and

FIG. 12 shows the rat pharmacokinetic profile of Example A, determinedby blood plasma analysis at defined time points after i.v. and p.o.administration to male SD rats.

FIG. 13 shows (A) concentration dependent inhibition and (B)concentration dependent reversal of in vitro cyst formation in a humanpatient-derived conditionally immortalised OX161 cell line by Example A.

DETAILED DESCRIPTION OF THE INVENTION

The invention is based on the surprising identification of new compoundsthat are able to activate long isoforms of PDE4 enzymes. The compoundsare small molecules and so are expected to be easier and cheaper to makeand formulate into pharmaceuticals than large biological molecules suchas polypeptides, proteins or antibodies. The compounds can be chemicallysynthesized, as demonstrated in the Examples.

The Examples demonstrate that a number of compounds of Formula 1 andFormula 2 are able to activate long isoforms of PDE4. The Examples go onto demonstrate that certain tested compounds of the invention: do notactivate a short form of PDE4, (thereby demonstrating selectivity foractivation of PDE4 long forms over PDE4 short forms); reduceintracellular cAMP levels in human and dog cells; inhibit and evenreverse in vitro cyst formation in human and dog cells; inhibit theproliferation of human prostate cancer cells; and have favourablepharmacokinetic properties. The compounds of the invention are thereforesurprisingly advantageous.

Various embodiments of the invention are described herein. It will berecognised that features specified in each embodiment may be combinedwith other specified features to provide further embodiments.

Compounds—Formula 1

A first aspect provides a compound of Formula 1, as set out above.

In an embodiment of the compound of Formula 1, R⁷ and R¹¹ are H.

In an embodiment of the compound of Formula 1, R¹¹, R¹², R¹³, R¹⁴ andR¹⁵ are H.

In an embodiment of the compound of Formula 1, R⁹ is selected from(C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the (C1-4)alkyl and(C1-4)alkyloxy groups being optionally substituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 1, R⁷, R¹¹, R¹², R¹³, R¹⁴and R¹⁵ are H and R⁹ is selected from (C1-4)alkyl, (C1-4)alkyloxy, CNand halogen, the (C1-4)alkyl and (C1-4)alkyloxy groups being optionallysubstituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 1, R¹ is H, methyl, ormethoxy.

In an embodiment of the compound of Formula 1, R¹ is methyl.

In an embodiment of the compound of Formula 1, R² and R⁶ are eachindependently selected from H and halogen.

In an embodiment of the compound of Formula 1, R² and R⁶ are eachindependently selected from H and fluoro.

In an embodiment of the compound of Formula 1, R² and R⁶ are each H.

In an embodiment of the compound of Formula 1, R³, R⁴ and R⁵ are eachindependently selected from H, halogen, CN, (C1-4)alkyl and(C1-4)alkyloxy, the (C1-4)alkyl and (C1-4)alkyloxy groups beingoptionally substituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 1, R³ and R⁵ are eachindependently selected from H, fluoro, chloro, methoxy, CN,trifluoromethyl, methoxy and trifluoromethoxy.

In an embodiment of the compound of Formula 1, R⁴ is selected from H,fluoro and methoxy.

In an embodiment of the compound of Formula 1, R⁹ is selected frommethyl, chloro and trifluoromethoxy.

In an embodiment of the compound of Formula 1, R⁹ is chloro.

In an embodiment of the compound of Formula 1, one of R⁸ and R¹⁰ is Hand the other is fluoro.

In an embodiment of the compound of Formula 1, R⁵ and R¹⁵ are both H.

In an embodiment of the compound of Formula 1, R⁹ is chloro, one of R⁸and R¹⁰ is H and the other of R⁸ and R¹⁰ is fluoro.

In an embodiment, the compound is selected from:

-   N-(3-Fluorobenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-Benzyl-2[3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-Benzyl-2-[3-(4-chlorophenyl)-5-methyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-(3-Fluorobenzyl)-2-{3-[4-(trifluoromethoxy)-phenyl]-5-methoxymethyl-1H-1,2,4-triazol-1-yl}acetamide;-   N-(3-Chlorobenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-(3-Cyanobenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-[3-(Trifluoromethyl)benzyl]-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-(3-Methoxybenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-[3-(Trifluoromethoxy)benzyl]-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-(2-Fluorobenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-(4-Fluorobenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;-   N-(3,4-Dimethoxybenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;    and pharmaceutically acceptable salts thereof.    Compounds—Formula 2

A further aspect provides a compound of Formula 2, as set out above.

In an embodiment of the compound of Formula 2, R⁷ and R¹¹ are H.

In an embodiment of the compound of Formula 2, R¹¹, R¹², R¹³, R¹⁴ andR¹⁵ are H.

In an embodiment of the compound of Formula 2, R⁹ is selected from(C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the (C1-4)alkyl and(C1-4)alkyloxy groups being optionally substituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 2, R⁷, R¹¹, R¹², R¹³, R¹⁴and R¹⁵ are H and R⁹ is selected from (C1-4)alkyl, (C1-4)alkyloxy, CNand halogen, the (C1-4)alkyl and (C1-4)alkyloxy groups being optionallysubstituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 2, R¹ is H, methyl, ormethoxy.

In an embodiment of the compound of Formula 2, R¹ is methyl.

In an embodiment of the compound of Formula 2, R² and R⁶ are eachindependently selected from H and halogen.

In an embodiment of the compound of Formula 2, R² and R⁶ are eachindependently selected from H and fluoro.

In an embodiment of the compound of Formula 2, R² and R⁶ are each H.

In an embodiment of the compound of Formula 2, R³, R⁴ and R⁵ are eachindependently selected from H, halogen, CN, (C1-4)alkyl and(C1-4)alkyloxy, the (C1-4)alkyl and (C1-4)alkyloxy groups beingoptionally substituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 2, R³ and R⁵ eachindependently selected from H, fluoro, chloro, methoxy, CN,trifluoromethyl, methoxy and trifluoromethoxy.

In an embodiment of the compound of Formula 2, R⁴ is selected from H,fluoro and methoxy.

In an embodiment of the compound of Formula 2, R⁹ is selected frommethyl, chloro and trifluoromethoxy.

In an embodiment of the compound of Formula 2, R⁹ is chloro.

In an embodiment of the compound of Formula 2, one of R⁸ and R¹⁰ is Hand the other is fluoro.

In an embodiment of the compound of Formula 2, R⁸ and R¹⁰ are both H.

In an embodiment of the compound of Formula 2, R⁹ is chloro, one of R⁸and R¹⁰ is H and the other of R⁸ and R¹⁰ is fluoro.

Intermediates of Formula 1A and 1C

Further aspects provide compounds of Formula 1A and 1C, as set outabove.

In an embodiment of the compound of Formula 1A, R⁷ and R¹¹ are H.

In an embodiment of the compound of Formula 1A, R⁹ is selected from(C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the (C1-4)alkyl and(C1-4)alkyloxy groups being optionally substituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 1A, R⁷ and R¹¹ are H and R⁹is selected from (C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the(C1-4)alkyl and (C1-4)alkyloxy groups being optionally substituted with1 to 3 fluoros.

In an embodiment of the compound of Formula 1A, R¹ is H, methyl, ormethoxy.

In an embodiment of the compound of Formula 1A, R¹ is methyl.

In an embodiment of the compound of Formula 1A, R⁹ is selected frommethyl, chloro and trifluoromethoxy.

In an embodiment of the compound of Formula 1A, R⁹ is chloro.

In an embodiment of the compound of Formula 1A, one of R⁸ and R¹⁰ is Hand the other is fluoro.

In an embodiment of the compound of Formula 1A, R⁸ and R¹⁰ are both H.

In an embodiment of the compound of Formula 1A, R⁹ is chloro, one of R⁸and R¹⁰ is H and the other of R⁸ and R¹⁰ is fluoro.

In an embodiment of the compound of Formula 10, R⁷ and R¹¹ are H.

In an embodiment of the compound of Formula 10, R¹¹, R¹² and R¹³ are H.

In an embodiment of the compound of Formula 1C, R⁹ is selected from(C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the (C1-4)alkyl and(C1-4)alkyloxy groups being optionally substituted with 1 to 3 fluoros.

In an embodiment of the compound of Formula 1C, R⁷, R¹¹, R¹² and R¹³ areH and R⁹ is selected from (C1-4)alkyl, (C1-4)alkyloxy, CN and halogen,the (C1-4)alkyl and (C1-4)alkyloxy groups being optionally substitutedwith 1 to 3 fluoros.

In an embodiment of the compound of Formula 10, R¹ is H, methyl, ormethoxy.

In an embodiment of the compound of Formula 1C, R¹ is methyl.

In an embodiment of the compound of Formula 10, R⁹ is selected frommethyl, chloro and trifluoromethoxy.

In an embodiment of the compound of Formula 1C, R⁹ is chloro.

In an embodiment of the compound of Formula 1C, one of R⁸ and R¹⁰ is Hand the other is fluoro.

In an embodiment of the compound of Formula 10, R⁸ and R¹⁰ are both H.

In an embodiment of the compound of Formula 10, R⁹ is chloro, one of R⁸and R¹⁰ is H and the other of R⁸ and R¹⁰ is fluoro.

Definitions

The term “(C1-4)alkyl” as used herein means a branched or unbranchedalkyl group having 1-4 carbon atoms, optionally containing a ring.Examples of (C1-4)alkyl include butyl, isobutyl, cyclobutyl, tertiarybutyl, propyl, isopropyl, cyclopropyl, ethyl and methyl. Where specifiedin the formulae above, (C1-4)alkyl may be substituted, for example with1 to 3 fluoros. A particularly preferred example of a substituted(C1-4)alkyl is trifluoromethyl. Alternatively (C1-4)alkyl may beunsubstituted.

The term “(C1-4)alkyloxy” means —O—(C1-4)alkyl wherein (C1-4)alkyl hasthe meaning as defined above. Examples of (C1-4)alkyloxy includemethoxy, ethoxy, propoxy, isopropoxy, butyoxy, isobutoxy and tertiarybutoxy. Where specified in the formulae above, (C1-4)alkyloxy may besubstituted, for example with 1 to 3 fluoros. A particularly preferredexample of a substituted (C1-4)alkyloxy is trifluoromethoxy.Alternatively, (C1-4)alkyloxy may be unsubstituted. In the presentinvention, alkyloxy is attached to the rest of the molecule by the “oxy”moiety.

The term “halogen” means F, Cl, Br or I. F and Cl are particularlypreferred.

The 1,2,4-triazole derivatives of Formula 1 or 2 may be prepared bymethods known in the art of organic chemistry in general. Suitablemethods for constructing 1,2,4-triazole rings are, for example,described in the general reference Katritzky, A. R.: Comprehensiveheterocyclic chemistry (First Edition, Pergamon Press, 1984, seeespecially Volume 5, Part 4A, Five-membered rings with two or morenitrogen atoms). Suitable protecting groups for functional groups whichare to be temporarily protected during syntheses are known in the art,for example from Wuts, P. G. M. and Greene, T. W.: Protective Groups inOrganic Synthesis, Fourth Edition, Wiley, New York, 2006.

Activation of Long PDE4 Isoforms

PDE4 long isoforms have two regulatory regions, upstream conservedregion 1 (UCR1) and upstream conserved region 2 (UCR2). These arebetween the isoform-specific N-terminal portion and the catalyticdomain. The UCR1 domain is missing in the short forms, whereas thesuper-short forms not only lack UCR1, but also have a N-terminaltruncated UCR2 domain (Houslay, M. D., Schafer, P. and Zhang, K. DrugDiscovery Today 10: 1503-1519, 2005).

There are four PDE4 families, PDE4A, PDE4B, PDE4C and PDE4D. The presentinvention concerns compounds that are capable of activating one or moreof the long isoforms from one or more of these four families. The longisoform PDE4 may therefore be long isoform PDE4A, long isoform PDE4B,long isoform PDE4C or long isoform PDE4D. For the avoidance of doubt, along isoform PDE4 comprises a UCR1 region. Typically, the long isoformPDE4 is human. UCR1 is conserved within mammalian species (Houslay, M D,Sullivan, M and Bolger G B Adv Pharmacol. 1998; 44:225-34), so in otherembodiments, the long isoform PDE4 can be from a non-human mammal.

Without wishing to be bound by theory, PDE4 long form activators ofFormula I or Formula II of the present invention are small moleculesthat are believed to bind directly to PDE4 long forms and inducestructural changes that increase, stabilise, uncover and/or maintain thecatalytic activity of these enzymes. In the field of pharmacology, andas used herein, a small molecule is defined as a low molecular weightorganic compound that may serve as a regulator of biological processes.A small molecule activator according to the present invention has amolecular weight of less than or equal to 700 Daltons. This allows forthe possibility to rapidly diffuse across cell membranes and reachintracellular sites of action (Veber, D. F. et al., J. Med. Chem. 45:2615-2623, 2002). The preferred molecular weight for a small moleculeactivator according to the present invention is greater than or equal to200 Daltons and less than or equal to 600 Daltons. Especially preferredsmall molecule activators according to the present invention havemolecular weights of greater than or equal to 250 Daltons and less thanor equal to 500 Daltons (Lipinski, C. A. Drug Discovery Today:Technologies 1: 337-341, 2004).

One suitable method of detecting whether or not a compound is capable ofserving as an activator of a PDE4 long form is using a two-stepradio-assay procedure described in Experiment 1. In summary, the methodinvolves incubating a PDE4 long form with a test small moleculeactivator, together with [³H]-labelled cAMP to assess alterations in thebreakdown of cAMP to the 5′-adenosine monophosphate (5′-AMP) product. Asample of the reaction mixture from such an incubation is subsequentlytreated with snake venom 5′-nucleotidase to allow conversion of thenucleotide [³H]-labelled 5′-AMP to the uncharged nucleoside[³H]-labelled adenosine, which can be separated and quantified to assessPDE4 activity and the effect of the test compound (Thompson, W. J. andAppleman, M. M. Biochemistry 10: 311-316, 1971, with some modificationsas described in: Marchmont, R. J. and Houslay, M. D. Biochem J. 187:381-92, 1980).

Using the above assay procedure, as described in detail in Experiment 1,preferred small molecule activators according to the present inventionproduce an increase in the background activity of one or more PDE4 longforms of more than 50% at a test compound concentration of 100micromolar or less. Especially preferred small molecule activatorsaccording to the present invention produce an increase in the backgroundactivity of one or more PDE4 long forms of more than 50% at a testcompound concentration of 10 micromolar, or less, for example 3micromolar.

The compounds of the present invention may be selective for the longform of the PDE4 enzyme and, as such, do not act or act to a lesserextent as activators of the short or super-short isoforms of the PDE4enzyme. The short or super-short isoform PDE4 may therefore be short orsuper-short isoform PDE4A, short or super-short isoform PDE4B, short orsuper-short isoform PDE4C, or short or super-short isoform PDE4D. Forthe avoidance of doubt, short and super-short isoforms of PDE4 lack aUCR1 domain. Super-short isoforms comprise a truncated UCR2 domain.Typically, the short or super-short isoform PDE4 is human, but may alsobe from other mammalian species (where UCR2 is conserved, see Houslay, MD, Sullivan, M and Bolger G B Adv Pharmacol. 1998; 44:225-34).

Under the same assay conditions, as described in Experiment 1, the smallmolecule activators according to the present invention typically producea less than 50% increase in the background activity of the short orsuper-short forms of the PDE4A, PDE4B, PDE4C or PDE4D enzymes at a testcompound concentration of 100 micromolar, or less.

Typical compounds may therefore provide a positive result in an assayfor activation of a long form PDE4 and a negative result in an assay foractivation of a short form (or super-short form) of PDE4. In oneembodiment, the compound activates long isoform PDE4A and does notactivate either of short and super-short isoform PDE4A. In anotherembodiment, the compound activates long isoform PDE4B and does notactivate either of short and super-short isoform PDE4B. In a furtherembodiment, the compound activates long isoform PDE4C and does notactivate either of short and super-short isoform PDE4C. In anotherembodiment, the compound activates long isoform PDE4D and does notactivate either of short and super-short isoform PDE4D.

PDE4 long isoforms include those now known as PDE4A4, PDE4A4/5, PDE4A5,PDE4A8, PDE4A10, PDE4A11, PDE4B1, PDE4B3, PDE4B4, PDE4C1, PDE4C2,PDE4C3, PDE4D3, PDE4D4, PDE4D5, PDE4D7, PDE4D8, PDE4D9 and PDE4D11.Further long isoforms may be or have already been identified or calledby different nomenclature from any of the four PDE4 sub-families.

PDE4 short isoforms include PDE4A1, PDE4B2, PDE4D1 and PDE4D2. Furthershort isoforms may be or have already been identified or called bydifferent nomenclature from any of the four PDE4 sub-families.

PDE4 super-short isoforms include PDE4B5, PDE4D6 and PDE4D10. Furthersuper-short isoforms may be or have already been identified or called bydifferent nomenclature from any of the four PDE4 sub-families.

The Examples below exemplify activity of compounds in human PDE4D5,PDE4A4 and PDE4B1 long isoforms and a lack of activity in the humanPDE4B2 short isoform. Details of these isoforms and a number of theother known isoforms, including GenBank accession numbers, are providedin Tables A to D immediately below.

TABLE A Examples of known PDE4A isoforms PDE4A calculated SDS- Isoformaccession size PAGE (kDa) Type  A1 (human) U97583 83 S A1 (rodent)M26715, L27062 76 S A4* (humanA5) L20965 125 L A5 (rodentA4) L27057 107L A7** (human) U18088 37 DS A8 (rodent) L36467 88 kDa 98 L A10 (human)AF110461 91 kDa 121 L A11 (human) AY618547 95 kDa 126 L L = Long; S =short; SS = Super-short; D = Dead short *Note that the PDE4A4B clone iscorrect while PDE4A4A has a cloning artefact and PDE4A4C is a truncationartefact. **Note that this species is C- as well as N-terminallytruncated and so will NOT be detected by pan PDE4A antisera that detectall active forms.

TABLE B Examples of known PDE4B Isoforms PDE4B Isoform accessionSDS-PAGE (kDa) Type B1 L20966 104 L B2 M97515, L20971 68 S B3 U85048 103L B4 AF202733 84 L B5 EF595686 58 SS L = Long; S = short; SS =Super-short; D = Dead short

TABLE C Examples of known PDE4C Isoforms PDE4C Isoform Name GenBank Size(aa) PDE4C1 (partial clone) L20968 251* (partial) PDE4C1 Z46632 712*(Long) PDE4C2 U88712  606 (Long) PDE4C3 U88713 700* (Long) PDE4C4 U66346791* (Long) PDE4C5 U66347 426* PDE4C6 U66348 518* PDE4C7 U66349 427*

TABLE D Examples of known PDE4D Isoforms PDE4D Isoform accessioncalculated SDS-PAGE (kDa) Type D1 U50157, U79571 66 kDa 68 S D2 U50158,AFO12074 66 kDa 68 S D3 L20970, U50159 77 kDa 95 L D4 L20969 91 kDa 119L D5 AFO12073 84 kDa 105 L D6 (m) AF536975 59 kDa 59 SS D7 AF536976 85kDa 103 L D8* AF536977 78 kDa 96 L D9 AY245867 77 kDa 95 L D10 DQ66589658 kDa 58 SS D11 EU489880 79 kDa 95 L L = Long; S = short; SS =Super-short; D = Dead short *nb D8 was originally called PDE4D6 in theliterature (m) Memory clones are (AY245867, AF536977, AF536976)Reduction of cAMP

Without wishing to be bound by theory, the compounds of the presentinvention may function by reducing cAMP levels in one or moreintracellular compartments. The PDE4 long form activators of the presentinvention may thus provide a means to regulate certain cellularprocesses that are dependent upon cAMP. Excessive intracellular cAMPsignalling mediates a number of diseases and disorders. Therefore, thecompounds of the invention are expected to be of utility for thetreatment of diseases associated with abnormally elevated cAMP levels,increased cAMP-mediated signalling and/or reduced cAMP elimination,enzymatic or otherwise (e.g. via efflux). The treatment is typically ofa human, but may also be of a non-human animal, such as a non-humanmammal (e.g. veterinary treatment).

In one aspect, the present invention provides a small molecule activatorof a PDE4 long form of Formula 1 or Formula 2, for use in a method forthe treatment or prevention of disorders where a reduction of secondmessenger responses mediated by cyclic 3′,5′-adenosine monophosphate(cAMP) is required.

For example, gain-of-function gene mutations in proteins involved indriving cAMP signalling upstream of adenylyl cyclase, such as GPCRs andGsα, can lead to abnormal excessive cAMP activity with pathologicalconsequences (Lania A, Mantovani G, Spada A. Ann Endocrinol (Paris). 73:73-75, 2012; Thompson, M. D. et al., Methods Mol. Biol. 448: 109-137,2008; Weinstein L S, Liu J, Sakamoto A, Xie T, Chen M. Endocrinology.145: 5459-5464, 2004; Lania A, Mantovani G, Spada A. Eur J Endocrinol.145: 543-559, 2001). PDE4 long form activators of the present invention,possessing the ability to accelerate the termination of cAMP action,would therefore be expected to be effective in the treatment, preventionor partial control of diseases characterised by undesirably high cAMPlevels, or activity, as detailed below.

Diseases Characterised by Elevated cAMP Levels

Hyperthyroidism

Stimulation of the thyroid-stimulating hormone (TSH) receptor (TSHR)leads to increased generation and release of thyroid hormones, thyroxineand triiodothyronine, through a cAMP-dependent signalling mechanisminvolving Gsα-mediated activation of adenylyl cyclase. Gain-of-functionmutations in the TSHR have been reported to be involved in thedevelopment of hyperthyroidism (Duprez, L. et al., Nat. Genet. 7:396-401, 1994; Biebermann, H. et al., J. Clin. Endocrinol. Metab. 86:4429-4433, 2001; Karges, B. et al., J. Endocrinol. 186: 377-385, 2005).Activating mutations of both TSHR and Gsα have also been found in goitreand thyroid adenomas (Arturi, F. et al., Exp. Clin. Endocrinol. Diabetes106: 234-236, 1998). The increased cAMP activity in thyroid adenomas, asa result of the activating TSHR or Gsα mutations, has been reported toproduce a protective adaptive increase in PDE4 activity to counteractabnormal rise in cAMP levels and signal transduction (Persani, L. etal., J. Clin. Endocrinol. Metab. 85: 2872-2878, 2000).

The most common cause of hyperthyroidism is Graves' disease, anautoimmune disorder in which antibodies mimic TSH action at the TSHR,leading to excessive cAMP activity in thyroid follicle cells andconsequently a state of hyperthyroidism.

PDE4 long form activators of the present invention are thereforeexpected to be effective in the treatment, prevention or partial controlof hyperthyroidism. In one embodiment, the hyperthyroidism is associatedwith Graves' disease.

Jansens's Metaphyseal Chondrodysplasia and Hyperparathyroidism

Jansens's Metaphyseal Chondrodysplasia (JMC) is a very rare diseaseresulting from gain-of-function mutations of the parathyroid hormone(PTH) receptor 1 (PTHR1) (Thompson, M. D. et al., Methods Mol. Biol.448: 109-137, 2008). The constitutive activation of the PTHR1 whichcouples to adenylyl cyclase as effector is associated with excessivecAMP signalling primarily in bone and kidney, leading to dysregulationof ion homeostasis characterised by hypercalcemia and hypophosphatemia(Calvi, L. M. and Schipani, E. J. Endocrinol. Invest. 23: 545-554, 2000)and developmental (e.g. short stature) and physical (e.g. protrudingeyes) abnormalities.

Primary hyperparathyroidism results from excessive release of PTH fromthe parathyroid gland due to tissue enlargement or non-cancerousadenoma. The resulting excessive stimulation of the PTHR1 receptorcauses disruption of plasma ion homeostasis with patients showinghypercalcemia and hypophosphatemia. PDE4 long form activators of thepresent invention are therefore expected to be effective in thetreatment, prevention or partial control of JMC and hyperparathyroidism.

Familial Male Precocious Puberty (Testotoxicosis)

Familial male-limited precocious puberty (FMPP), also known as familialsexual precocity or gonadotropin-independent testotoxicosis, is adisorder in which boys generally develop signs of precocious puberty inearly childhood.

The spinal length in boys may be short due to a rapid advance inepiphyseal maturation. FMPP is an autosomal dominant condition withconstitutively activating mutations in the luteinizing hormone (LH)receptor, which leads to increased cAMP production, associated withLeydig cell hyperplasia and low sperm cell count (Latronico, A. C. etal., J Clin. Endocrinol. Metab. 80: 2490-2494, 1995; Kosugi, S. et al.,Hum. Mol. Genet. 4: 183-188, 1995). PDE4 long form activators of thepresent invention are therefore expected to be effective in thetreatment, prevention or partial control of FMPP.

Pituitary Adenomas and Cushing's Disease

Non-cancerous tumours of the pituitary gland are collectively referredto as pituitary adenomas and can lead to hypersecretion ofadenohypophyseal hormones (e.g. growth hormone, thyroid stimulatinghormone, luteinizing hormone, follicle stimulating hormone andadrenocorticotrophic hormone), which exert their action through GPCRscoupled to Gs and cAMP generation. Thus pituitary adenomas can lead to astate of enhanced cAMP mediated signalling in a variety of endocrinetissues which can precipitate a number of hormonal disorders such asacromegly (mainly due to excess growth hormone secretion), Cushing'sdisease (due to overproduction of adrenocorticotrophic hormone (ACTH)and the subsequent hypercortisolemia) and/or general hyperpituitarism(associated with excess release of multiple anterior pituitaryhormones). Current treatment options for pituitary adenomas includetreatment with dopamine receptor agonists, which reduce tumour size andlower pituitary hormonal output through a mechanism involving loweringof intracellular cAMP levels. PDE4 long form activators of the presentinvention may also be expected to attenuate the pathological effects ofpituitary hormones in their target tissues, such as the adrenal glands.

In Cushing's disease, pituitary adenoma related overproduction of ACTHcan lead to hypercortisolemia through an overactivation of melanocortin2 receptor (MC2) and subsequent cAMP mediated stimulation ofsteroidogenesis and release of cortisol from the adrenal cortex (Tritos,N. A. and Biller, B. M. Discov. Med. 13: 171-179, 2012). PDE4 long formactivators of the present invention are therefore expected to beeffective in the treatment, prevention or partial control of Cushing'sdisease.

Polycystic Kidney Disease

Polycystic kidney disease (PKD) is a genetic disorder of the kidneyscharacterised by development of pathological cysts, which damage renalstructure and compromise kidney function (Takiar, V. and Caplan, M. J.Biochim. Biophys. Acta. 1812: 1337-1343, 2011; Masoumi, A. et al., Drugs67: 2495-2510, 2007). There are two types of PKD: autosomal dominantpolycystic kidney disease (ADPKD) and autosomal recessive polycystickidney disease (ARPKD). ADPKD affects between 0.1% and 0.2% of thepopulation worldwide and is characterized by progressive cystdevelopment and enlarged kidneys. Approximately 50% of people with thisdisease will develop end stage kidney disease, usually between 40 and 70years of age and require dialysis or kidney transplantation. ARPKDaffects around 1:20,000 live births and is typically identified in thefirst few weeks after birth. Pulmonary hypoplasia results in a 30-50%death rate in neonates with ARPKD.

Defects in two genes are thought to be responsible for ADPKD. In around85% of patients, development of ADPKD can be linked to mutations in thegene PKD1, encoding polycystin-1 (PC-1); in around 15% of patientsmutations in PKD2, encoding polycystin-2 (PC-2) are implicated. CyclicAMP has been identified as an important stimulus for proliferation andcyst expansion in polycystic kidney cells but not in normal human kidneycells (Yamaguchi, T. et al., Kidney Int. 57: 1460-1471, 2000). Aconsiderable body of evidence has now developed to implicate cAMP as animportant facilitator of renal cystogenesis (Masoumi, A. et al., Drugs67: 2495-2510, 2007; Wallace, D. P. Biochim. Biophys. Acta. 1812:1291-1300, 2011). Consistent with the role of cAMP in cyst formation,agents that lower cAMP levels (e.g. vasopressin V2 receptor antagonistsand the somatostatin receptor agonist octreotide) showed efficacy inrodent models of PKD (Torres, V. E. et al., Nat. Med. 10: 363-364, 2004;Gattone, V. H. 2^(nd) et al., Nat. Med. 9: 1323-1326, 2003; Belibi, F.A. and Edelstein, C. L. Expert Opin. Investig. Drugs. 19: 315-328,2010). In zebrafish embryos, depletion of a cAMP-hydrolysing PDE enzymesubtype, PDE1A, resulted in development of a cystic phenotype, whilePDE1A over-expression partially rescued cystic phenotypes resulting fromPC2 depletion (Sussman, C. R Ward, C. J., Leightner, A. C., Smith, J.L., Agarwal, R., Harris, P. C., Torres, V. E. J. Am. Soc. Nephrol. 25:2222-2230, 2014). Phosphodiesterase activation has been suggested as atherapeutic strategy for PKD treatment (Sun, Y., Zhou, H. and Yang, B-X.Acta Pharmacologica Sinica 32: 805-816, 2011).

PDE4 long form activators of the present invention are thereforeexpected to be effective in the treatment, prevention or partial controlof polycystic kidney disease.

The Examples, in particular FIGS. 7 and 8, show the inhibition andreversal of in vitro cyst formation in dog MDCK cells treated with aPDE4 long form activator—Example A—using the methods described inExperiment 3, with addition of the specified concentrations of the testcompounds every 2 days from day 0 to day 20, and Experiment 4, withaddition of the specified concentrations of the test compounds every 2days from day 10 to day 20.

The Examples, in particular FIG. 13, show the inhibition and reversal ofin vitro cyst formation in human OX161 cells treated with a PDE4 longform activator—Example A—using the methods described in Experiment 9,with addition of the specified concentrations of the test compound every2 days from day 0 to day 10, and Experiment 10, with addition of thespecified concentrations of the test compound every 2 days from day 10to day 20.

This provides experimental confirmation of the rationale that compoundsof the invention are able to treat diseases and disorders mediated bycAMP.

Polycystic Liver Disease

Polycystic liver disease (PLD) is a rare inherited condition associatedwith hepatic cystogenesis (usually defined when number of cysts exceeds20), which often occurs in association with ADPKD (Strazzabosco, M. andSomlo, S. Gastroenterology 140: 1855-1859, 2011; Gevers, T. J. andDrenth, J. P. Curr. Opin. Gastroenterol. 27: 294-300, 2010). PLD mayhave a different genetic pathology when compared to ADPKD, driven bymutated proteins associated with the endoplasmic reticulum and thecilium. Increased cholangiocyte proliferation, neovascularisation andelevated fluid secretion act to drive liver cyst formation throughdysregulation of multiple signal transduction pathways, includingcAMP-mediated signalling. Elevation of hepatic cAMP levels stimulatescAMP-dependent chloride and fluid secretion in biliary epithelial cellsand increases cholangiocyte proliferation (Janssen, M. J. et al., J.Hepatol. 52: 432-440, 2010). Somatostatin, which acts through aGi-coupled mechanism to lower cAMP levels, reduced cholangiocyteproliferation and fluid secretion (Gong, A. Y. et al., Am. J. Physiol.Cell. Physiol. 284: C1205-1214, 2003). Furthermore, the syntheticsomatostatin analogue, octreotide, showed efficacy in an animal model ofPLD through a mechanism involving reduction in cAMP signalling (Masyuk,T. V. et al., Gastroenterology 132: 1104-1116, 2007). PDE4 long formactivators of the present invention may therefore be effective in thetreatment, prevention or partial control of polycystic liver disease dueat least in part to cAMP.

Maturity Onset Diabetes of Young Type 5 (MODY5)

MODY5 is a form of non-insulin-dependent diabetes mellitus associatedwith renal cysts. It is an autosomal dominant disorder caused bymutations in the gene encoding hepatocyte nuclear factor-1β (HNF-1β).The predominant clinical feature of patients affected by MODY5 is renaldysfunction, frequently diagnosed before the onset of diabetes. In somepatients, HNF-1β mutations can result in additional phenotypic features,such as pancreatic atrophy, abnormal liver function and genital tractabnormalities. Studies in mice suggest that the mechanism responsiblefor renal cyst formation, associated with mutations of HNF-1β, involvesa severe defect of the transcriptional activation of PKD2, in additionto effects on uromodulin (UMOD) and PKD1 genes. Down-regulation of PKD1and PKD2 is associated with cAMP-driven formation of renal cysts(Mancusi, S. et al., J. Nephrol. 26: 207-12, 2013). HNF-1β also binds tothe PDE4C promoter and regulates the expression of PDE4C (Ma et al.,PNAS 104: 20386, 2007).

PDE4 long form activators of the present invention are thereforeexpected to be effective in the treatment, prevention or partial controlof the symptoms of MODY5.

Cardiac Hypertrophy, Heart Failure and Arrhythmia

Localized regulation and integration of cAMP signalling are importantfor proper cardiac function and perturbation of this signalling can leadto heart failure. Upon chronic β-adrenergic receptor stimulation,cardiomyocyte hypertrophy is induced via elevated cAMP and activation ofits downstream effectors, including PKA and Epac (Wang, L. et al., Cell.Signal. 27: 908-922, 2015 and references therein). Cardiomyocytehypertrophy increases the risk of heart failure and arrhythmia.

PDE4 long form activators of the present invention may therefore beeffective in the treatment, prevention or partial control of cardiachypertrophy, heart failure and/or arrhythmia.

Diseases Associated with Increased cAMP-mediated Signalling

Disorders Associated with Activating Mutations of the Alpha Subunit ofthe G Protein (GNAS1)

The G-protein Gs acts as a transducer for GPCRs that stimulate adenylylcyclase activity and exert their biological effects by increasingintracellular cAMP levels. Gs is a heterotrimeric protein composed of α,β and γ subunits. Activating mutations in the gene, GNAS1, for theα-subunit have been identified which lead to exaggerated abnormal cAMPsignalling in a variety of tissues and give rise to a range ofdisorders.

McCune-Albright syndrome

McCune-Albright syndrome (MAS) is a rare genetic disorder typicallycharacterised by three dominating features of precocious puberty,fibrous dysplasia of bone and café au lait lesions. The underlyingmolecular pathology for MAS involves an activating mutation of the GNAS1gene (Diaz, A. Danon, M. and Crawford, J. J. Pediatr. Endocrinol. Metab.20: 853-880, 2007). PDE4 long form activators of the present inventionwould therefore be expected to be effective in the treatment, preventionor partial control of disorders associated with activating mutations ofGNAS1, including McCune-Albright syndrome.

Amelioration of Toxin-induced Increases in Adenylyl Cyclase Activity inInfectious Diseases.

Adenylyl cyclase, the enzyme responsible for production of cAMP, is akey biological target thought to be involved in mediating the effects ofmany bacterial toxins (Ahuja et al., Critical Reviews in Microbiology,30: 187-196, 2004). These toxins produce their effects by raising cAMPlevels through enhancement of host immune cell and/or pathogen relatedadenylyl cyclase activity. PDE4 long form activators of the presentinvention, by reducing cAMP levels, would therefore be expected to be ofutility in the treatment or partial control of symptoms of infectiousdiseases that are associated with elevated cAMP activity. The followingare some examples of such infectious diseases:

Cholera

Vibrio cholerae produces cholera toxin, which through adenosinedisphosphate ribosylation of the α subunit of Gs leads to host celladenylyl cyclase activation and cAMP production. Diarrhoea caused bycholera toxin is believed to be a result of excessive cAMP accumulationin the cells of the gastrointestinal tract.

Whooping Cough

Bordetella pertussis is the pathogen responsible for the childhooddisease whooping cough. Bordetella pertussis toxin stimulates adenosinedisphosphate ribosylation of the α subunit of Gi and indirectly augmentscAMP levels in target cells. The bacterium also secretes an invasiveadenylyl cyclase, which produces toxic cAMP levels and impairs hostimmune defence.

Anthrax

Anthrax is caused by Bacillus anthracis and whilst it is primarily ananimal disease it can be transmitted to humans through contact. Anthraxinfections are associated with widespread oedema, the development ofwhich is thought to be driven by oedema toxin. The latter is an adenylylcyclase and is activated by host calmodulin to produce abnormally highlevels of cAMP that have a toxic effect on host immune cells.

Tuberculosis

Mycobactrium tuberculosis expresses a large and diverse range ofadenylyl cyclases, which may play a role in virulence and generation ofdisease pathology. One adenylyl cyclase subtype, RV0386, has beendemonstrated to enter host macrophages and elevate intracellular cAMP tocause toxicity (Agarwal et al., Nature, 460: 98-102, 2009).

PDE4 long form activators of the present invention may therefore beeffective in the treatment, prevention or partial control of infectiousdiseases such as cholera, whooping cough, anthrax and tuberculosis.

Diseases Dependent Upon Activation of PKA by Elevated cAMP.

In eukaryotes, cAMP activates protein kinase A (PKA), which is alsoknown as cAMP-dependent protein kinase. PKA is normally inactive as atetrameric holoenzyme, consisting of two catalytic and two regulatoryunits, with the regulatory units blocking the catalytic centres of thecatalytic units. cAMP binds to specific locations on the regulatoryunits of PKA and causes dissociation between the regulatory andcatalytic units, thus activating the catalytic units. The activecatalytic units catalyse the transfer of phosphate from ATP to specificresidues of protein substrates, which may modulate the function of thoseprotein substrates.

PDE4 long form activation reduces cAMP levels and cAMP mediatedactivation of PKA. PDE4 long form activators of the present inventionwould therefore be expected to be of utility in the treatment or partialcontrol of disorders where inhibitors of PKA show evidence oftherapeutic effects.

Disorders that are dependent upon activation of PKA by cAMP may beidentified by their response to PKA inhibitors such as Rp-8-Br-cAMPS.Rp-8-Br-cAMPS is an analogue of cAMP that occupies the cAMP bindingsites of PKA, preventing its dissociation and activation.

HIV Infection and AIDS

T cells from HIV-infected patients have increased levels of cAMP and aremore sensitive to inhibition by Rp-8-Br-cAMPS than are normal T cells.Excessive activation of PKA by cAMP has been associated with theprogressive T cell dysfunction in HIV infection (Aandahl, E. M. et al.,FASEB J. 12: 855-862, 1998). Furthermore, in vivo administration ofRp-8-Br-cAMPS has been shown to restore T cell responses inretrovirus-infected mice (Nayjib, B. et al., The Open ImmunologyJournal, 1: 20-24, 2008). PDE4 long form activators of the presentinvention are therefore expected to be of utility in the treatment,prevention or partial control of HIV infection and AIDS.

Common Variable Immunodeficiency (CVID)

In vitro administration of Rp-8-Br-cAMPS has been shown to correctimpaired secretion of the cytokine IL-10 by T cells from patients withCommon Variable Immunodeficiency (CVID) (Holm, A. M. et al., J. Immunol.170: 5772-5777, 2003). PDE4 long form activators of the presentinvention are therefore expected to be of utility in the treatment,prevention or partial control of CVID.

Diseases Dependent Upon Activation of Either or Both of Epac1 and Epac2by Elevated cAMP.

In addition to PKA, cAMP activates another intracellular receptor, knownas exchange protein directly activated by cAMP (Epac). There are twoisoforms of Epac, Epac1 and Epac2, both consisting of a regulatoryregion that binds cAMP and a catalytic region that promotes the exchangeof GDP for GTP on the small G proteins, Rap1 and Rap2 of the Ras family.In addition, Epac proteins exert their functions through interactionswith a number of other cellular partners at specific cellular loci.Pathophysiological changes in Epac signalling have been associated witha wide range of diseases (Breckler, M. et al., Cell. Signal. 23:1257-1266, 2011).

Relevant disorders that are dependent upon activation of Epac proteinsby cAMP may be identified by their response to Epac inhibitors, such asESI-09, a novel non-cyclic nucleotide Epac1 and Epac2 antagonist that iscapable of specifically blocking intracellular Epac-mediated Raptactivation and Akt phosphorylation, as well as Epac-mediated insulinsecretion in pancreatic beta cells (Almahariq, M. et al., Mol.Pharmacol. 83: 122-128, 2013).

Melanoma

Epac1 has been implicated in promoting migration and metastasis inmelanoma (Baljinnyam, E. et al., Pigment Cell Melanoma Res. 24: 680-687,2011 and references cited therein).

PDE4 long form activators of the present invention are thereforeexpected to be of utility in the treatment, prevention or partialcontrol of melanoma.

Pancreatic Cancer

It has recently been shown that Epac1 is markedly elevated in humanpancreatic cancer cells as compared with normal pancreas or surroundingtissue (Lorenz, R. et al., Pancreas 37: 102-103, 2008).

Pancreatic cancer is often resistant to treatments that are usuallyeffective for other types of cancer. Using the Epac inhibitor ESI-09, afunctional role of Epac1 overexpression in pancreatic cancer cellmigration and invasion was demonstrated (Almahariq, M. et al., Mol.Pharmacol. 83: 122-128, 2013). These findings are consistent withresults based on RNAi silencing techniques and suggest that inhibitionof Epac1 signalling could be an effective therapeutic strategy forpancreatic cancer.

PDE4 long form activators of the present invention would therefore beexpected to be of utility in the treatment, prevention or partialcontrol of pancreatic cancer.

Diseases Dependent Upon Modulation of cAMP-gated Ion Channels byElevated cAMP.

In addition to activation of PKA and Epac, another effector pathway forelevated cAMP is the activation of cAMP-gated ion channels. PDE4 longform activators of the present invention would therefore be expected tobe of utility in the treatment of disorders where inhibitors ofcAMP-gated ion channels show evidence of therapeutic effects.

Diseases Associated with Increased Activity of cAMP Response ElementBinding Protein.

The cAMP response element binding protein (CREB) is an importanttranscription factor involved in the regulation of a variety of cellularfunctions such as cell proliferation, differentiation, survival, andapoptosis (Cho et al., Crit Rev Oncog, 16: 37-46, 2011). CREB activityis regulated by kinase dependant phosphorylation through a range ofextracellular signals, such as stress, growth factors andneurotransmitters. Phosphorylation leads to dimerisation of CREB, andtogether with other co-activator partner proteins, enables it to bind topromoter regions of target genes containing the cAMP response element(CRE sites) and initiate transcriptional activity. The cAMP pathway(e.g. through cAMP-dependant protein kinase mediated phosphorylation) isan important positive modulator of CREB mediated biological activity.PDE4 long form activators of the present invention are thereforeexpected to be of utility in the treatment, prevention or partialcontrol of disorders associated with elevated CREB activity.

Leukaemia

Bone marrow cells from acute lymphoid and myeloid leukaemia patientshave been reported to overexpress CREB protein and mRNA (Crans-Vargas etal., Blood, 99: 2617-9, 2002; Cho et al., Crit Rev Oncog, 16: 37-46,2011). Furthermore, the increased CREB level correlates with poorclinical response in subjects with acute myeloid leukaemia (Grans-Vargaset al., Blood, 99: 2617-9, 2002; Shankar et al., Cancer Cell, 7:351-62,2005). Upregulation of CREB is associated with stimulation of humanleukaemia cell growth whilst downregulation inhibits myeloid cellproliferation and survival. PDE4 long form activators of the presentinvention would be expected to reduce CREB activity and function throughattenuation of cAMP mediated stimulation of CREB and therefore expectedto have utility in the treatment, prevention or partial control of acutelymphoid and myeloid leukaemia.

Prostate Cancer

Abnormal excessive androgen activity is an important driver in thedevelopment of prostate cancer as it stimulates the development ofintraepithelial neoplasias (Merkle et al., Cellular Signalling, 23:507-515, 2011). This is strongly supported by the use of androgenablation approaches, involving chemical or surgical castration, in thetreatment of prostate cancer. Cyclic AMP elevating agents such asforskolin can enhance androgen receptor activity through multipleintracellular mechanisms including androgen receptor activation throughphosphorylation and/or interaction with CREB. Epac1 activation has alsobeen implicated in promoting cellular proliferation in prostate cancer(Misra, U. K. and Pizzo, S. V. J. Cell. Biochem. 108: 998-1011, 2009;Misra, U. K. and Pizzo, S. V. J. Cell. Biochem. 113: 1488-1500, 2012).PDE4 long form activators of the present invention are thereforeexpected to have utility in the treatment, prevention or partial controlof prostate cancer.

The Examples demonstrate that compounds of the invention are able toinhibit the proliferation of prostate cancer cells. This providesexperimental confirmation of the rationale that compounds of theinvention are able to treat diseases and disorders mediated by cAMP.

Diseases Associated with Reduced Activity of cAMP-hydrolysing PDEEnzymes

Loss-of-function mutations in gene(s) for cAMP-hydrolysing PDE isoformsother than PDE4, such as PDE8 and PDE11, have been detected in a numberof diseases (Vezzosi, D. and Bertherat, J., Eur. J. Endocrinol. 165:177-188, 2011; Levy, I. et al., Curr. Opin. Pharmacol. 11: 689-697,2011; Azevedo, M. F. and Stratakis, C. A. Endocr. Pract. 17 Suppl 3:2-7, 2011). These mutations can lead to abnormally high cAMP levelsand/or duration of cAMP action with pathological consequences asdetailed below. PDE4 long form activators of the present invention aretherefore expected to be of utility in the treatment, prevention orpartial control of these diseases, such as adrenocortical tumours,testicular cancer, PPNAD and Carney Complex.

Adrenocortical Tumours

Adrenocortical tumours associated with an inactivating point mutation inthe gene encoding PDE11A4 have decreased expression of PDE11A4 andincreased cAMP levels (Horvath, A. et al., Nat Genet. 38: 794-800, 2006;Horvath, A. et al., Cancer Res. 66: 11571-11575, 2006; Libe, R., et al.,Clin. Cancer Res. 14: 4016-4024, 2008).

Testicular Cancer

Mutations that reduce PDE11A activity and increase cAMP levels have beenobserved in some forms of testicular cancer (Horvath. A. et al., CancerRes. 69: 5301-5306, 2009).

Primary Pigmented Nodular Adrenocortical Diseases (PPNAD)

Mutations in the PDE8B gene have also been identified as a predisposingfactor for PPNAD and the mutant protein shows reduced ability to degradecAMP (Horvath, A., Mericq, V. and Stratakis, C. A. N. Engl. J. Med. 358:750-752, 2008; Horvath, A. et al., Eur. J. Hum. Genet. 16: 1245-1253,2008).

Carney Complex

In Carney Complex (CNC) caused by PRKAR1A mutations, some patients alsohave defects in PDE11A that may exert a synergistic effect to enhanceabnormal activation of the cAMP signal transduction pathway, leading toadrenal and testicular cancer (Libe, R. et al., J. Clin. Endocrinol.Metab. 96: E208-214, 2011).

Treatment and Posology

By “treatment” herein is meant the treatment by therapy, whether of ahuman or a non-human animal (e.g., in veterinary applications) typicallya non-human mammal, in which some desired therapeutic effect on thecondition is achieved; for example, the inhibition of the progress ofthe disorder, including a reduction in the rate of progress, a halt inthe rate of progress, amelioration of the disorder or cure of thecondition. Treatment as a prophylactic measure is also included.References herein to prevention or prophylaxis herein do not indicate orrequire complete prevention of a condition; its manifestation mayinstead be reduced or delayed via prophylaxis or prevention according tothe present invention.

By a “therapeutically effective amount” herein is meant an amount of theone or more compounds of the invention or a pharmaceutical formulationcomprising such one or more compounds, which is effective for producingsuch a therapeutic effect, commensurate with a reasonable benefit/riskratio.

It will be appreciated that appropriate dosages of the compounds of theinvention may vary from patient to patient. Determining the optimaldosage will generally involve the balancing of the level of therapeuticbenefit against any risk or deleterious side effects of the treatmentsof the present invention. The selected dosage level will depend on avariety of factors including the activity of the particular compound,the route of administration, the time of administration, the rate ofexcretion of the compound, the duration of the treatment, other drugs,compounds or materials used in combination and the age, sex, weight,condition, general health and prior medical history of the patient. Theamount of compound(s) and route of administration will ultimately be atthe discretion of the physician, although generally the dosage will beto achieve local concentrations at the site of action so as to achievethe desired effect. Administration in vivo can be effected in one dose,continuously or intermittently throughout the course of treatment.Methods of determining the most effective means and dosage ofadministration are well known to a person skilled in the art and willvary with the formulation used for therapy, the purpose of the therapy,the target cell being treated, and the subject being treated. Single ormultiple administrations can be carried out with the dose level andpattern being selected by the treating physician.

In general, a suitable dose of the one or more compounds of theinvention may be in the range of about 0.001 to 50 mg/kg body weight ofthe subject per day, preferably in a dosage of 0.01-25 mg per kg bodyweight per day, e.g., 0.01, 0.05, 0.10, 0.25, 0.50, 1.0, 2.5, 10 or 25mg/kg per day. Where the compound(s) is a salt, solvate, prodrug or thelike, the amount administered may be calculated on the basis of theparent compound and so the actual weight to be used may be increasedproportionately.

Combination Therapies

The compounds of the invention may also find application in mimicking orenhancing the effects of drugs known to produce their therapeutic effectthrough lowering of intracellular cAMP levels.

A number of therapeutically beneficial drugs have a primary mode ofaction involving lowering intracellular cAMP levels and/or cAMP-mediatedactivity, as summarised below. Since PDE4 long form activators of thepresent invention will also act to lower cAMP levels it is expected thatthese agents will mimic and/or augment the pharmacological propertiesand therapeutic utility of drugs operating through a down-regulation ofcAMP-mediated signalling. In certain embodiments, a compound of theinvention is therefore provided as part of a combination therapy withanother agent that lowers intracellular cAMP levels and/or cAMP-mediatedactivity. The combination therapy may be administered simultaneously,contemporaneously, sequentially or separately. In one embodiment, thecompound of the invention and the separate cAMP lowering agent areprovided in a single composition, as described in more detail below. Thecombination therapy may comprise a compound of the invention and one ormore of:

-   -   (i) a presynaptic α-2 adrenergic receptor agonist, optionally        clonidine, dexmedetomidine, or guanfacine;    -   (ii) a β-1 Adrenergic receptor antagonist (“beta-blocker”),        optionally Atenolol, Metoprolol, Bisoprolol, Acebutolol, or        Betaxolol.        Combination with α-2 Adrenergic Receptor Agonist

α-2 Adrenergic receptor stimulation is known to reduce cAMP levelsthrough a G_(i) protein-mediated inhibition of adenylyl cyclase activityin a broad range of tissues. In noradrenergic neurones in the brain andperipheral sympathetic nervous system, presynaptic α-2 adrenergicreceptor activation inhibits noradrenaline release and noradrenergicactivity. Drugs (e.g. clonidine, dexmedetomidine, guanfacine) that actas agonists at these receptors are effective in the treatment of avariety of clinical conditions. Clonidine, the prototypic agent, hasshown therapeutic utility in the treatment of hypertension, neuropathicpain, opioid detoxification, insomnia, ADHD, Tourette syndrome, sleephyperhidrosis, addiction (narcotic, alcohol and nicotine withdrawalsymptoms), migraine, hyperarousal, anxiety and also as a veterinaryanaesthetic. Lowering of cAMP levels by PDE4 long form activation may beexpected to yield similar effects to drugs acting through α-2 adrenergicreceptor stimulation. Furthermore, PDE4 long form activators of thepresent invention may be expected to potentiate the pharmacodynamiceffects of α-2 adrenergic receptor agonists when used in combination.

Combination with β-1 Adrenergic Receptor Antagonist

β-1 Adrenergic receptor antagonists are used in the treatment a range ofcardiovascular indications including hypertension, cardiac arrhythmiasand cardioprotection following myocardial infarction. Their primarymechanism of action involves reducing the effects of excessivecirculating adrenaline and sympathetic activity, mediated bynoradrenaline, particularly at cardiac β-1 adrenergic receptors.Endogenous and synthetic β-1 adrenergic receptor agonists stimulateadenylyl cyclase activity through G_(s) activation and raiseintracellular cAMP levels in a variety of tissues such as heart andkidney. Consequently, drugs that block β-1 adrenergic receptor mediatedactivity exert their pharmacological effects by attenuating the increasein cAMP mediated signalling. Given that PDE4 long form activation willalso lower cAMP concentration and transduction in cardiac tissue, PDE4long form activators of the present invention may be expected to findutility in the treatment or partial control of hypertension, cardiacarrhythmias, congestive heart failure and cardioprotection. Additionalnon-cardiovascular therapeutic utility may be expected in disorders suchas post-traumatic stress related disorder, anxiety, essential tremor andglaucoma, which also respond to β-1 adrenergic antagonist treatment.Furthermore, PDE4 long form activators of the present invention may beexpected to potentiate the pharmacodynamic effects of β-1 adrenergicreceptor antagonists when used in combination.

Methods of Treatment

In a further aspect, the present invention provides a small moleculeactivator of a PDE4 long form of Formula 1 or Formula 2 for use in amethod for the treatment or prevention of a disease or disorder in apatient in need of such therapy. The disease or disorder may be anydisease of disorder described herein, including: a disease associatedwith increased cAMP production and signalling (such as hyperthyroidism,Jansens's metaphyseal chondrodysplasia, hyperparathyroidism, familialmale-limited precocious puberty, pituitary adenomas, Cushing's disease,polycystic kidney disease, polycystic liver disease, MODY5 and cardiachypertrophy); diseases known to be associated with increasedcAMP-mediated signalling, including disorders associated with activatingmutations of the alpha subunit of the G protein (GNAS1) (such asMcCune-Albright syndrome); amelioration of toxin-induced increases inadenylyl cyclase activity in infectious diseases (such as cholera,whooping cough, anthrax, and tuberculosis); treatment of diseases knownto be dependent upon activation of PKA by elevated cAMP (such as HIVinfection and AIDS, and Common Variable Immunodeficiency (CVID));treatment of diseases known to be dependent upon activation of either orboth of Epac1 and Epac2 by elevated cAMP (such as melanoma andpancreatic cancer); treatment of diseases dependent upon modulation ofcAMP-gated ion channels by elevated cAMP; treatment of diseases known tobe associated with increased activity of cAMP response element bindingprotein (such as leukaemia and prostate cancer); treatment of diseasesknown to be associated with reduced activity of cAMP-hydrolysing PDEenzymes (such as adrenocortical tumours, testicular cancer, primarypigmented nodular adrenocortical diseases (PPNAD) and Carney Complex);and mimicking or enhancing the effects of drugs known to produce theirtherapeutic effect through lowering of intracellular cAMP levels.

As used herein, the terms “compound of the invention”, “compound ofFormula 1”, “compound of Formula 2” etc. include pharmaceuticallyacceptable derivatives thereof and polymorphs, isomers and isotopicallylabelled variants thereof. Furthermore, these terms include all thesub-embodiments of those compounds disclosed herein.

Pharmaceutically Acceptable Derivatives

The present invention further provides pharmaceutical compositionscomprising a compound of the invention, including a pharmaceuticallyacceptable salt, solvate, ester, hydrate or amide thereof, in admixturewith a pharmaceutically acceptable excipient(s), and optionally othertherapeutic agents. The term “acceptable” means being compatible withthe other ingredients of the composition and not deleterious to therecipient thereof. Compositions include e.g. those suitable for oral,sublingual, subcutaneous, intravenous, epidural, intrathecal,intramuscular, transdermal, intranasal, pulmonary, topical, local, orrectal administration, and the like, typically in unit dosage forms foradministration.

The term “pharmaceutically acceptable salt” includes a salt preparedfrom pharmaceutically acceptable non-toxic acids or bases includinginorganic or organic acids and bases. Compounds of the invention whichcontain basic, e.g. amino, groups are capable of formingpharmaceutically acceptable salts with acids. Examples ofpharmaceutically acceptable acid addition salts of the compoundsaccording to the invention include acid addition salts formed withorganic carboxylic acids such as acetic, lactic, tartaric, maleic,citric, pyruvic, oxalic, fumaric, oxaloacetic, isethionic, lactobionicand succinic acids; organic sulfonic acids such as methanesulfonic,ethanesulfonic, benzenesulfonic and p-toluenesulfonic acids andinorganic acids such as hydrochloric, sulfuric, phosphoric and sulfamicacids.

Compounds of the invention which contain acidic, e.g. carboxyl, groupsare capable of forming pharmaceutically acceptable salts with bases.Pharmaceutically acceptable basic salts of the compounds of theinvention include, but are not limited to, metal salts such as alkalimetal or alkaline earth metal salts (e.g. sodium, potassium, magnesiumor calcium salts) and zinc or aluminium salts and salts formed withammonia or pharmaceutically acceptable organic amines or heterocyclicbases such as ethanolamines (e.g. diethanolamine), benzylamines,N-methyl-glucamine, amino acids (e.g. lysine) or pyridine.

Hemisalts of acids and bases may also be formed, e.g. hemisulphatesalts.

Pharmaceutically acceptable salts of compounds of the compounds of theinvention may be prepared by methods well-known in the art. For a reviewof pharmaceutically acceptable salts, see Stahl and Wermuth, Handbook ofPharmaceutical Salts: Properties, Selection and Use (Wiley-VCH,Weinheim, Germany, 2002).

Prodrugs

The invention includes prodrugs of the compounds of Formulae 1 and 2.Prodrugs are derivatives of compounds of Formula 1 or 2 (which may havelittle or no pharmacological activity themselves), which can, whenadministered in vivo, be converted into compounds of Formula 1 or 2.

Prodrugs can, for example, be produced by replacing functionalitiespresent in the compounds of Formula 1 or 2 with appropriate moietieswhich are metabolized in vivo to form a compound of Formula 1 or 2. Thedesign of prodrugs is well-known in the art, as discussed in Bundgaard,Design of Prodrugs 1985 (Elsevier), The Practice of Medicinal Chemistry2003, 2^(nd) Ed, 561-585 and Leinweber, Drug Metab. Res. 1987, 18: 379.

Examples of prodrugs of compounds of Formula 1 or 2 are amides andesters of those compounds. For example, where the compound of Formula 1or 2 contains a carboxylic acid group (—COOH), the hydrogen atom of thecarboxylic acid group may be replaced in order to form an ester (e.g.the hydrogen atom may be replaced by C₁₋₆alkyl). Where a compoundcontains an alcohol group (—OH), the hydrogen atom of the alcohol groupmay be replaced in order to form an ester (e.g. the hydrogen atom may bereplaced by —C(O)C₁₋₆alkyl.

Solvates

It may be convenient or desirable to prepare, purify, and/or handle acorresponding solvate of the compounds described herein, which may beused in the any one of the uses/methods described. The term solvate isused herein to refer to a complex of solute, such as a compound or saltof the compound, and a solvent. If the solvent is water, the solvate maybe termed a hydrate, for example a mono-hydrate, di-hydrate, tri-hydrateetc, depending on the number of water molecules present per molecule ofsubstrate.

Stereoisomers

It will be appreciated that the compounds of the present invention mayexist in various stereoisomeric forms and the compounds of the presentinvention as hereinbefore defined include all stereoisomeric forms andmixtures thereof, including enantiomers and racemic mixtures. Thepresent invention includes within its scope the use of any suchstereoisomeric form or mixture of stereoisomers, including theindividual enantiomers of the compounds of Formula 1 or 2 as well aswholly or partially racemic mixtures of such enantiomers. Whereappropriate isomers can be separated from their mixtures by theapplication or adaptation of known methods (e.g. chromatographictechniques and recrystallisation techniques). Where appropriate isomerscan be prepared by the application or adaptation of known methods (e.g.asymmetric synthesis).

Isotopes

The invention includes pharmaceutically acceptable isotopically-labelledcompounds of Formula 1 or 2 wherein one or more atoms are replaced byatoms having the same atomic number, but an atomic mass or mass numberdifferent from the atomic mass or mass number usually found in nature.

Examples of isotopes suitable for inclusion in the compounds of theinvention include isotopes of hydrogen, such as ²H and ³H, carbon, suchas ¹¹C, ¹³C and ¹⁴C, chlorine, such as ³⁸Cl, fluorine, such as ¹⁸F,iodine, such as ¹²³I and ¹²⁵I, nitrogen, such as ¹³N and ¹⁵N, oxygen,such as ¹⁵O, ¹⁷O and ¹⁸O, and sulphur, such as ³⁵S. Certainisotopically-labelled compounds of Formula 1 or 2, for example, thoseincorporating a radioactive isotope, are useful in drug and/or substratetissue distribution studies. The radioactive isotopes ³H and ¹⁴C areparticularly useful for this purpose in view of their ease ofincorporation and ready means of detection. Substitution with positronemitting isotopes, such as ¹¹C, ¹⁸F, ¹⁵O and ¹³N, can be useful inPositron Emission Topography (PET) studies for examining substratereceptor occupancy. Isotopically-labelled compounds of Formula 1 or 2can generally be prepared by conventional techniques known to thoseskilled in the art or by processes analogous to those described hereinusing an appropriate isotopically-labelled reagent in place of thenon-labelled reagent previously employed.

Pharmaceutical Compositions

For oral administration, the active ingredient may be presented asdiscrete units, such as tablets, capsules, powders, granulates,solutions, suspensions, and the like.

Formulations suitable for oral administration may also be designed todeliver the compounds of the invention in an immediate release manner orin a rate-sustaining manner, wherein the release profile can be delayed,pulsed, controlled, sustained, or delayed and sustained or modified insuch a manner which optimises the therapeutic efficacy of the saidcompounds. Means to deliver compounds in a rate-sustaining manner areknown in the art and include slow release polymers that can beformulated with the said compounds to control their release.

Examples of rate-sustaining polymers include degradable andnon-degradable polymers that can be used to release the said compoundsby diffusion or a combination of diffusion and polymer erosion. Examplesof rate-sustaining polymers include hydroxypropyl methylcellulose,hydroxypropyl cellulose, methyl cellulose, ethyl cellulose, sodiumcarboxymethyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone,xanthum gum, polymethacrylates, polyethylene oxide and polyethyleneglycol.

Liquid (including multiple phases and dispersed systems) formulationsinclude emulsions, suspensions, solutions, syrups and elixirs. Suchformulations may be presented as fillers in soft or hard capsules (made,for example, from gelatin or hydroxypropylmethylcellulose) and typicallycomprise a carrier, for example, water, ethanol, polyethylene glycol,propylene glycol, methylcellulose, or a suitable oil, and one or moreemulsifying agents and/or suspending agents. Liquid formulations mayalso be prepared by the reconstitution of a solid, for example, from asachet.

The compounds of the invention may also be used in fast-dissolving,fast-disintegrating dosage forms such as those described in Liang andChen, Expert Opinion in Therapeutic Patents 2001, 11(6): 981-986.

The formulation of tablets is discussed in H. Lieberman and L. Lachman,Pharmaceutical Dosage Forms: Tablets 1980, vol. 1 (Marcel Dekker, NewYork).

For administration intranasally or by inhalation, the active ingredientmay be presented in the form of a dry powder from a dry powder inhaleror in the form of an aerosol spray of a solution or suspension from apressurised container, pump, spray, atomiser or nebuliser.

For parenteral administration, the pharmaceutical composition of theinvention may be presented in unit-dose or multi-dose containers, e.g.injection liquids in predetermined amounts, for example in sealed vialsand ampoules, and may also be stored in a freeze dried (lyophilized)condition requiring only the addition of sterile liquid carrier, e.g.water, prior to use.

For parenteral administration, the compounds of the invention may beadministered directly into the blood stream, into subcutaneous tissue,into muscle, or into an internal organ. Suitable means foradministration include intravenous, intraarterial, intrathecal,intraventricular, intraurethral, intrasternal, intracranial,intramuscular, intrasynovial and subcutaneous. Suitable devices foradministration include needle (including microneedle) injectors,needle-free injectors and infusion techniques.

Parenteral formulations are typically aqueous or oily solutions. Wherethe solution is aqueous, excipients such as sugars (including butrestricted to glucose, mannitol, sorbitol, etc.) salts, carbohydratesand buffering agents (preferably to a pH of from 3 to 9), but, for someapplications, they may be more suitably formulated as a sterilenon-aqueous solution or as a dried form to be used in conjunction with asuitable vehicle such as sterile, pyrogen-free water (WFI).

Parenteral formulations may include implants derived from degradablepolymers such as polyesters (i.e. polylactic acid, polylactide,polylactide-co-glycolide, polycapro-lactone, polyhydroxybutyrate),polyorthoesters and polyanhydrides. These formulations may beadministered via surgical incision into the subcutaneous tissue,muscular tissue or directly into specific organs.

The preparation of parenteral formulations under sterile conditions, forexample, by lyophilisation, may readily be accomplished using standardpharmaceutical techniques well known to those skilled in the art.

The solubility of compounds of the invention used in the preparation ofparenteral solutions may be increased by the use of appropriateformulation techniques, such as the incorporation of co-solvents and/orsolubility-enhancing agents such as surfactants, micelle structures andcyclodextrins.

Mixed with such pharmaceutically acceptable excipients, e.g. asdescribed in the standard reference, Gennaro, A. R. et al, Remington:The Science and Practice of Pharmacy (21st Edition, Lippincott Williams& Wilkins, 2005, see especially Part 5: Pharmaceutical Manufacturing),the active agent may be compressed into solid dosage units, such aspills, tablets, or be processed into capsules, suppositories or patches.By means of pharmaceutically acceptable liquids the active agent can beapplied as a fluid composition, e.g. as an injection preparation or asan aerosol spray, in the form of a solution, suspension, or emulsion.

For making solid dosage units, the use of conventional additives such asfillers, colorants, polymeric binders and the like is contemplated. Ingeneral any pharmaceutically acceptable additive that does not interferewith the function of the active compounds can be used. Suitable carrierswith which the active agent of the invention can be administered assolid compositions include lactose, starch, cellulose derivatives andthe like, or mixtures thereof, used in suitable amounts. For parenteraladministration, aqueous suspensions, isotonic saline solutions andsterile injectable solutions may be used, containing pharmaceuticallyacceptable dispersing agents and/or wetting agents, such as propyleneglycol or butylene glycol.

The invention further includes a pharmaceutical composition, ashereinbefore described, in combination with packaging material suitablefor said composition, said packaging material including instructions forthe use of the composition for the use as hereinbefore described.

In some embodiments, the one or more compounds of the present inventionmay be used in combination therapies for the treatment of the describedconditions i.e., in conjunction with other therapeutic agents. For thecase of active compounds combined with other therapies the two or moretreatments may be given in individually varying dose schedules and viadifferent routes.

The combination of the agents listed above with a compound of thepresent invention would be at the discretion of the physician who wouldselect dosages using his common general knowledge and dosing regimensknown to a skilled practitioner.

Where a compound of the invention is administered in combination therapywith one, two, three, four or more, preferably one or two, preferablyone other therapeutic agents, the compounds can be administeredsimultaneously or sequentially. When administered sequentially, they canbe administered at closely spaced intervals (for example over a periodof 5-10 minutes) or at longer intervals (for example 1, 2, 3, 4 or morehours apart, or even longer period apart where required), the precisedosage regimen being commensurate with the properties of the therapeuticagent(s).

In one embodiment, the invention provides a product comprising acompound of the invention and another therapeutic agent as a combinedpreparation for simultaneous, separate or sequential use in therapy. Inone embodiment, the therapy is the treatment or prevention of disorderswhere a reduction of second messenger responses mediated by cyclic3′,5′-adenosine monophosphate (cAMP) is required. Products provided as acombined preparation include a composition comprising a compound of theinvention and the other therapeutic agent together in the samepharmaceutical composition, or the compound of the invention and theother therapeutic agent in separate form, e.g. in the form of a kit.

In one embodiment, the invention provides a pharmaceutical compositioncomprising a compound of the invention and another therapeutic agent.Optionally, the pharmaceutical composition may comprise apharmaceutically acceptable excipient, as described above.

In one embodiment, the invention provides a kit comprising two or moreseparate pharmaceutical compositions, at least one of which contains acompound of the invention. In one embodiment, the kit comprises meansfor separately retaining said compositions, such as a container, dividedbottle, or divided foil packet. An example of such a kit is a blisterpack, as typically used for the packaging of tablets, capsules and thelike.

The kit of the invention may be used for administering different dosageforms, for example, oral and parenteral, for administering the separatecompositions at different dosage intervals, or for titrating theseparate compositions against one another. To assist compliance, the kitof the invention typically comprises directions for administration.

In the combination therapies of the invention, the compound of theinvention and the other therapeutic agent may be manufactured and/orformulated by the same or different manufacturers. Moreover, thecompound of the invention and the other therapeutic may be broughttogether into a combination therapy: (i) prior to release of thecombination product to physicians (e.g. in the case of a kit comprisingthe compound of the invention and the other therapeutic agent); (ii) bythe physician themselves (or under the guidance of the physician)shortly before administration; (iii) in the patient themselves, e.g.during sequential administration of the compound of the invention andthe other therapeutic agent.

Method of Manufacture & Method of Treatment

The invention also provides the use of a compound of the invention inthe manufacture of a medicament for the treatment or prevention ofdisorders where a reduction of second messenger responses mediated bycyclic 3′,5′-adenosine monophosphate (cAMP) is required, wherein themedicament is prepared for administration with another therapeuticagent. The invention also provides the use of another therapeutic agentin the manufacture of medicament for treating a disease or conditionmediated by cAMP for the treatment or prevention of disorders where areduction of second messenger responses mediated by cyclic3′,5′-adenosine monophosphate (cAMP) is required, wherein the medicamentis prepared for administration with a compound of the invention.

The invention also provides a compound of the invention for use in thetreatment or prevention of disorders where a reduction of secondmessenger responses mediated by cyclic 3′,5′-adenosine monophosphate(cAMP) is required, wherein the compound of the invention is preparedfor administration with another therapeutic agent. The invention alsoprovides another therapeutic agent for use in the treatment orprevention of disorders where a reduction of second messenger responsesmediated by cyclic 3′,5′-adenosine monophosphate (cAMP) is required,wherein the other therapeutic agent is prepared for administration witha compound of the invention. The invention also provides a compound ofthe invention for use in for the treatment or prevention of disorderswhere a reduction of second messenger responses mediated by cyclic3′,5′-adenosine monophosphate (cAMP) is required, wherein the compoundof the invention is administered with another therapeutic agent. Theinvention also provides another therapeutic agent for use in thetreatment or prevention of disorders where a reduction of secondmessenger responses mediated by cyclic 3′,5′-adenosine monophosphate(cAMP) is required, wherein the other therapeutic agent is administeredwith a compound of the invention.

The invention also provides the use of a compound of the invention inthe manufacture of a medicament for the treatment or prevention ofdisorders where a reduction of second messenger responses mediated bycyclic 3′,5′-adenosine monophosphate (cAMP) is required, wherein thepatient has previously (e.g. within 24 hours) been treated with anothertherapeutic agent. The invention also provides the use of anothertherapeutic agent in the manufacture of a medicament for the treatmentor prevention of disorders where a reduction of second messengerresponses mediated by cyclic 3′,5′-adenosine monophosphate (cAMP) isrequired, wherein the patient has previously (e.g. within 24 hours) beentreated with a compound of the invention.

In one embodiment, the other therapeutic agent is:

-   -   (i) a presynaptic α-2 adrenergic receptor agonist, optionally        clonidine, dexmedetomidine, or guanfacine;    -   (ii) a δ-1 Adrenergic receptor antagonist (“beta-blocker”),        optionally Atenolol, Metoprolol, Bisoprolol, Acebutolol, or        Betaxolol.

EXAMPLES

The present invention will now be further described by way of thefollowing non-limiting examples and with reference to the Tables andFigures:

Table 1 shows examples of novel small molecule PDE4 long form activatorsof Formula 1 and Formula 2 (Examples A to L), according to the presentinvention;

Table 2 shows activation of PDE4D5, a long form of PDE4, by Examples Ato L.

Table 3 shows activation of PDE4A4, another long form of PDE4, byExample A.

Table 4 shows activation of PDE4B1, another long form of PDE4, byExample A.

FIG. 1 shows activation of PDE4D5, a long form of PDE4, by Examples A,B, D and L.

FIG. 2 shows activation of PDE4A4, another long form of PDE4, by ExampleA.

FIG. 3 shows activation of PDE4B1, another long form of PDE4, by ExampleA.

FIG. 4 shows a lack of effect on PDE4B2, a short form of PDE4, ExamplesA, B, D and L.

FIG. 5 shows a reduction in intracellular cAMP levels in HEK 293 cellstreated with a PDE4 long form activator of the present invention (10 μM)for 10 min prior to forskolin (F) (10 μM) for 2 min.

FIG. 6 shows a reduction in intracellular cAMP levels in Madin-Darbycanine kidney (MDCK) cells treated with PDE4 long form activators of thepresent invention (10 μM) for 10 min prior to forskolin (F) (10 μM) for2 min.

FIG. 7 shows inhibition of in vitro cyst formation in MDCK cells treatedwith a PDE4 long form activator of the present invention.

FIG. 8 shows reversal of in vitro cyst formation in MDCK cells treatedwith a PDE4 long form activator of the present invention.

FIG. 9 shows inhibition of proliferation of androgen-sensitive (AS)LNCaP human prostate cancer cells treated with a PDE4 long formactivator of the present invention.

FIG. 10 shows inhibition of proliferation of androgen-insensitive (AI)LNCaP human prostate cancer cells treated with a PDE4 long formactivator of the present invention.

FIG. 11 shows the in vivo mouse pharmacokinetic profile of Example A,determined by whole blood analysis at defined time points after i.v. andp.o. administration to male C57 mice.

FIG. 12 shows the in vivo rat pharmacokinetic profile of Example A,determined by blood plasma analysis at defined time points after i.v.and p.o. administration to male SD rats.

FIG. 13 shows (A) inhibition and (B) reversal of in vitro cyst formationin OX161 cells treated with Example A, a PDE4 long form activator of thepresent invention.

Experimental Details

Preparation of Novel PDE4 Long Form Activators of Formula 1 and Formula2

Reactions were monitored by thin layer chromatography (Merck MilliporeTLC Silica Gel 60 F₂₅₄). Flash column chromatography was performed onPhenomenex Strata® pre-packed silica gel columns. NMR spectra wererecorded using a Bruker AV300 spectrometer at 25° C. The followingabbreviations are used in the assignment of NMR signals: s (singlet), d(doublet), t (triplet), q (quartet), m (multiplet), bs (broad singlet),dd (doublet of doublet), dt (doublet of triplet).

Example AN-(3-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamideStep 1: N-(3-Fluorobenzyl)-2-chloroacetamide

To a stirred solution of 3-fluorobenzylamine (3.32 g, 26.6 mmol) andtriethylamine (3.87 mL, 27.9 mmol) in dry dichloromethane (80 mL) at −5°C. (salt/ice bath) under argon was added chloroacetyl chloride (2.22 mL,27.9 mmol), dropwise over 10 minutes. The reaction mixture was stirredat −5° C. for a further 30 minutes, then stirred at room temperature for2 hours. The mixture was then diluted with chloroform (50 mL), washedwith saturated aqueous sodium bicarbonate solution (3×20 mL) and thenbrine (3×20 mL). The organic layer was then dried over anhydrous sodiumsulfate, filtered through a 2 cm silica gel pad, washing with 2%methanol in chloroform, and the filtrate concentrated under reducedpressure to afford N-(3-fluorobenzyl)-2-chloroacetamide as a white solid(5.15 g, 25.5 mmol).

Step 2: N-(3-Fluorobenzyl)-2-iodoacetamide

To a stirred solution of N-(3-fluorobenzyl)-2-chloroacetamide (5.13 g,25.4 mmol) in acetonitrile (50 mL) was added sodium iodide (4.00 g, 26.7mmol). The mixture was refluxed at 90° C. (oil bath) for 3 h and thenallowed to cool to room temperature. The precipitate was filtered offusing a short pad of Celite®, washing with dichloromethane. The filtratewas concentrated under reduced pressure to afford crude product as alight brown solid. The crude product was purified by flash columnchromatography, eluting with 5% to 35% ethyl acetate in petroleum ether,to afford N-(3-fluorobenzyl)-2-iodoacetamide as a pale yellow powder(7.11 g, 24.3 mmol).

Step 3: 4-Chloro-3-fluorobenzene carboximidic acid methyl ester,hydrochloride salt

Hydrochloric acid solution in methanol (3N; 3 mL), chlorotrimethylsilane(3.26 g, 30.0 mmol) and 4-chloro-3-fluorobenzonitrile (2.33 g, 15 mmol)were added sequentially to a dry reaction tube, with stirring underargon at room temperature. The mixture was heated to 50° C. withstirring for 1 h, during which time a thick white precipitate formed inthe mixture. Cyclopentyl methyl ether (5 mL) was added and the mixturewas heated to 50° C. for a further 1 h, with periodic shaking to loosenthe precipitate. The mixture was then allowed to cool to roomtemperature and the solid filtered off, washing with cyclopentyl methylether (2×5 mL) to afford 4-chloro-3-fluorobenzene carboximidic acidmethyl ester, hydrochloride salt (1.43 g, 6.9 mmol).

Step 4: 3-(4-Chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazole

A mixture of 4-chloro-3-fluorobenzene carboximidic acid methyl ester,hydrochloride salt (187 mg, 0.83 mmol), hydrazine hydrate (0.88 mL, 18.0mmol) and aluminium chloride (120 mg, 0.90 mmol) in toluene (30 mL) washeated to reflux for 3 h. The mixture was concentrated under reducedpressure, taken up in toluene and concentrated under reduced pressuretwice more. The residue was suspended in a toluene/acetonitrile mixture(12:1, 26 mL), propionyl chloride (0.36 mL, 4.1 mmol) was added and themixture was heated at 112° C. overnight. The mixture was concentratedunder reduced pressure and purified by flash column chromatography,eluting with 20% to 25% ethyl acetate in petroleum ether, to afford3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazole (28 mg, 0.12mmol).

Step 5:N-(3-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

To a stirred solution of3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazole (28 mg, 0.12 mmol)in dimethyl formamide (2 mL) under argon at 0° C. was added sodiumhydride (60% dispersion in mineral oil, 6.3 mg, 0.16 mmol). After 10minutes, a solution of N-(3-fluorobenzyl)-2-iodoacetamide (46 mg, 0.16mmol) in dimethylformamide (3 mL) was added dropwise. The reaction wasallowed to warm to room temperature and stirred for 72 h. The mixturewas concentrated under reduced pressure and then partitioned betweenchloroform (25 mL) and water (10 mL). The organic layer was separated,washed with brine (2×10 mL), dried over anhydrous magnesium sulphate,filtered and concentrated under reduced pressure. The crude product waspurified by flash column chromatography, eluting with 25% to 35% ethylacetate in petroleum ether and the product recrystallized fromchloroform/methanol to affordN-(3-fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamideas a white solid (15.3 mg, 0.039 mmol).

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.89-7.80 (2H, m), 7.56-7.43 (1H, m),7.38-7.22 (1H, m), 7.00 (3H, m), 6.62 (1H, s), 4.87 (2H, s), 4.50 (2H,d, J 5.9), 2.85 (2H, q, J 7.6), 1.41 (3H, t, J 7.6).

Example BN-Benzyl-2-[3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazol-1-yl]acetamideStep 1: N-Benzyl-2-chloroacetamide

To a stirred solution of benzylamine (7.64 mL, 70.0 mmol) andtriethylamine (10.22 mL, 73.5 mmol) in toluene (70 mL) at −5° C.(salt/ice bath) was added chloroacetyl chloride (5.85 mL, 73.5 mmol),dropwise over 10 minutes. The reaction mixture was stirred at −5° C. fora further 30 minutes, then stirred at room temperature for 2 hours. Themixture was then diluted with ethyl acetate (70 mL), washed withsaturated aqueous sodium bicarbonate solution (3×30 mL) and brine (3×30mL). The organic layer was then dried over anhydrous sodium sulphate,filtered and concentrated under reduced pressure to affordN-benzyl-2-chloroacetamide as a white solid (11.01 g, 59.96 mmol).

Step 2: N-Benzyl-2-iodoacetamide

To a stirred solution of N-benzyl-2-chloroacetamide (12.43 g, 67.66mmol) in acetonitrile (60 mL) was added sodium iodide (10.65 g, 71.04mmol). The mixture was gently refluxed at 95° C. (oil bath) for 2.5hours and then allowed to cool to room temperature. The precipitate wasfiltered off using a short pad of Celite®, washing with ethyl acetate.The filtrate was concentrated under reduced pressure to afford crudeproduct as a light brown solid. Trituration with an ethylacetate/dichloromethane mixture followed by filtration affordedN-benzyl-2-iodoacetamide (3.91 g). The filtrate was concentrated underreduced pressure and purified by flash column chromatography elutingwith 50% chloroform/ethyl acetate to afford further product (2.35 g).The pad of Celite® was further washed with dichloromethane and thenchloroform to afford further product (7.10 g). The product samples werecombined and dried in air to afford a single batch ofN-benzyl-2-iodoacetamide as a white powder (13.14 g, 47.76 mmol).

Step 3: 3-(4-Chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazole

To a solution of sodium methoxide in dry methanol (0.5M; 4 mL) was added4-chlorobenzonitrile (1.38 g, 10 mmol). The resulting suspension wasstirred at room temperature under argon for 2.5 h. A solution ofmethoxyacetic acid hydrazide (1.04 g, 10 mmol) in dry methanol (10 mL)was added to the mixture, resulting in a clear solution, which washeated to reflux for 3 h and then stirred at room temperature overnight.The mixture was concentrated under reduced pressure and purified byflash column chromatography eluting with 20% to 60% ethyl acetate inpetroleum ether to afford3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazole as a white solid(412 mg, 1.84 mmol).

Step 4:N-Benzyl-2-[3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazol-1-yl]acetamide

To a stirred solution of3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazole (45 mg, 0.20 mmol)in dimethyl formamide (2 mL) under argon at 0° C. was added sodiumhydride (60% dispersion in mineral oil, 9.6 mg, 0.24 mmol). After 10minutes, a solution of N-benzyl-2-iodoacetamide (66 mg, 0.24 mmol) indimethylformamide (3 mL) was added dropwise. The reaction was allowed towarm to room temperature and stirred for 72 h. The mixture wasconcentrated under reduced pressure and then partitioned betweendichloromethane (25 mL) and water (10 mL). The organic layer wasseparated, washed with brine (2×10 mL), dried over anhydrous magnesiumsulphate, filtered and concentrated under reduced pressure. The crudeproduct was purified by flash column chromatography, eluting with 40% to50% ethyl acetate in petroleum ether and the product recrystallized fromchloroform/methanol/hexane to affordN-benzyl-2[3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazol-1-yl]acetamideas a white solid (22 mg, 0.059 mmol).

¹H NMR: δ_(H) (300 MHz, CDCl₃) 8.07-7.96 (2H, m), 7.49-7.39 (2H, m),7.38-7.19 (5H, m), 6.48 (1H, s), 5.01 (2H, s), 4.70 (2H, s), 4.50 (2H,d, J 5.8), 3.40 (3H, s).

Example CN-Benzyl-2-[3-(4-chlorophenyl)-5-methyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example B,using acethydrazide instead of methoxyacetic acid hydrazide.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 8.05-7.93 (2H, m), 7.47-7.39 (2H, m),7.38-7.23 (5H, m), 6.64 (1H, s), 4.85 (2H, s), 4.50 (2H, d, J 5.8), 2.55(3H, s).

Example DN-(3-Fluorobenzyl)-2-{3-[4-(trifluoromethoxy)phenyl]-5-methoxymethyl-1H-1,2,4-triazol-1-yl}acetamide

The title compound was prepared according to the method of Example B,steps 3 and 4, using 4-(trifluoromethoxy)benzonitrile instead of4-chlorobenzonitrile and N-(3-fluorobenzyl)-2-iodoacetamide (as preparedin Example A) instead of N-benzyl-2-iodoacetamide.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 8.08-8.12 (2H, m), 7.19-7.34 (3H, m),6.91-7.01 (3H, m), 6.45 (1H, bs), 5.00 (2H, s), 4.68 (2H, s), 4.46 (2H,d, J 5.9), 3.42 (3H, s).

Example EN-(3-Chlorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamideStep 1: 3-(4-Chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazole

The triazole was prepared according to the method of Example B, step 3,using 4-chloro-3-fluorobenzonitrile instead of 4-chlorobenzonitrile andpropionic acid hydrazide instead of methoxyacetic acid hydrazide.

Step 2:O-tert-butyl-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetate

To a stirred solution of3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazole (492 mg, 2.18mmol) in dimethylformamide (10 mL) at room temperature under argon wasadded sodium hydride (60% dispersion in mineral oil, 105 mg, 2.62 mmol).After 10 minutes, tert-butylbromoacetate (386 μL, 2.62 mmol) was addeddropwise over 1 minute. The reaction was stirred at room temperature for18 h. The mixture was concentrated under reduced pressure and thenpurified by flash column chromatography, eluting with 5% to 15% ethylacetate in petroleum ether to affordO-tert-butyl-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetateas a white solid (661 mg, 1.94 mmol).

Step 3:2-[3-(4-Chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetic acid

To a stirred solution ofO-tert-butyl-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetate(661 mg, 1.94 mmol) in dichloromethane (30 mL) at 0° C. was addedtrifluoroacetic acid (10 mL) dropwise over 5 minutes. The reaction wasallowed to warm to room temperature and stirred for 18 h. The mixturewas concentrated under reduced pressure to afford crude2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetic acidas a viscous light brown oil, which was used without furtherpurification.

Step 4:2-[3-(4-Chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetylchloride

To a stirred solution of2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetic acid(crude material from step 3, ca. 1.94 mmol) in dichloromethane (30 mL)was added thionyl chloride (2.32 mL, 32.0 mmol). The mixture was heatedunder reflux for 6 h. The mixture was concentrated under reducedpressure to afford crude2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetylchloride (ca. 1.94 mmol), which was taken up in dichloromethane (33 mL)and used without further purification.

Step 5:N-(3-Chlorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

To a stirred solution of 3-chlorobenzylamine (39 mg, 0.27 mmol) andtriethylamine (63 μL, 0.45 mmol) in dichloromethane at 0° C. was added2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetylchloride (crude material from step 4, ca. 0.18 mmol) in dichloromethane(3 mL). The reaction was allowed to warm to room temperature and stirredfor 18 h. The mixture was concentrated under reduced pressure and thenpurified by flash column chromatography, eluting with 0.5% to 1%methanol in dichloromethane to afford a white solid, which was furtherpurified by trituration with chloroform and hexane to affordN-(3-chlorobenzyl)-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamideas a white solid (30.4 mg, 0.075 mmol).

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.84 (1H, dd, J 9.9, 1.8), 7.79 (1H, ddd,J 8.3, 1.9, 0.8), 7.44 (1H, dd, J 8.2, 7.6), 7.19-7.25 (3H, m),7.08-7.12 (1H, m), 6.59 (1H, bs), 4.84 (2H, s), 4.45 (2H, d, J 5.9),2.82 (2H, q, J 7.6), 1.38 (3H, t, J 7.6).

Example FN-(3-Cyanobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 3-cyanobenzylamine instead of 3-chlorobenzylamine in Step 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.78-7.86 (2H, m), 7.53-7.59 (2H, m),7.40-7.49 (3H, m), 6.71 (1H, bs), 4.85 (2H, s), 4.50 (2H, d, J 6.2),2.82 (2H, q, J 7.6), 1.38 (3H, t, J 7.6).

Example GN-[3-(Trifluoromethyl)benzyl]-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 3-(trifluoromethyl)benzylamine instead of 3-chlorobenzylamine inStep 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.83 (1H, dd, J 9.9, 1.8), 7.78 (1H, ddd,J 8.3, 1.9, 0.8), 7.51-7.56 (1H, m), 7.41-7.47 (4H, m), 6.64 (1H, bs),4.85 (2H, s), 4.53 (2H, d, J 6.0), 2.82 (2H, q, J 7.6), 1.37 (3H, t, J7.6).

Example HN-(3-Methoxybenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 3-methoxybenzylamine instead of 3-chlorobenzylamine in Step 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.83 (1H, dd, J 9.9, 1.9), 7.78 (1H, ddd,J 8.3, 1.9, 0.8), 7.43 (1H, dd, J 8.2, 7.5), 7.21 (1H, d, J 8.0),6.74-6.82 (3H, m), 6.53 (1H, bs), 4.83 (2H, s), 4.44 (2H, d, J 5.7),3.76 (3H, s), 2.81 (2H, q, J 7.6), 1.37 (3H, t, J 7.6).

Example IN-[3-(Trifluoromethoxy)benzyl]-2[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 3-(trifluoromethoxy)benzylamine instead of 3-chlorobenzylamine inStep 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.84 (1H, dd, J 9.9, 1.8), 7.79 (1H, ddd,J 8.3, 1.9, 0.8), 7.44 (1H, dd, J 8.2, 7.5), 7.34 (1H, t, J 7.9),7.11-7.17 (2H, m), 7.06-7.08 (1H, m), 6.61 (1H, bs), 4.85 (2H, s), 4.49(2H, d, J 6.0), 2.81 (2H, q, J 7.6), 1.37 (3H, t, J 7.6).

Example JN-(2-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 2-fluorobenzylamine instead of 3-chlorobenzylamine in Step 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.84 (1H, dd, J 10.0, 1.9), 7.81-7.78(1H, m), 7.42-7.47 (1H, m), 7.19-7.33 (2H, m), 7.00-7.12 (2H, m), 6.68(1H, bs), 4.80 (2H, s), 4.51 (2H, d, J 5.9), 2.79 (2H, q, J 7.6), 1.35(3H, t, J 7.6).

Example KN-(4-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 4-fluorobenzylamine instead of 3-chlorobenzylamine in Step 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.83 (1H, dd, J 10.0, 1.8), 7.77 (1H,ddd, J 8.3, 1.9, 0.8), 7.44 (1H, dd, J 8.2, 7.5), 7.16-7.22 (2H, m),6.96-7.04 (2H, m), 6.51 (1H, bs), 4.82 (2H, s), 4.43 (2H, d, J 5.9),2.80 (2H, q, J 7.6), 1.36 (3H, t, J 7.6).

Example LN-(3,4-Dimethoxybenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide

The title compound was prepared according to the method of Example E,using 3,4-dimethoxybenzylamine instead of 3-chlorobenzylamine in Step 5.

¹H NMR: δ_(H) (300 MHz, CDCl₃) 7.85 (1H, dd, J 10.0, 1.8), 7.77 (1H,ddd, J 8.3, 1.9, 0.8), 7.44 (1H, dd, J 8.0, 7.7), 6.73-6.81 (3H, m),6.45 (1H, bs), 4.82 (2H, s), 4.40 (2H, d, J 5.7), 3.86 (3H, s), 3.81(3H, s), 2.81 (2H, q, J 7.6), 1.37 (3H, t, J 7.6).

Biological Assays

Cell Culture

HEK 293 and MDCK cells (Public Health England, Cell Culture Collections)were maintained in DMEM supplemented with 10% (v/v) fetal bovine serum(Seralab), 2 mM L-glutamine, 1,000 U penicillin and 1,000 μgstreptomycin (Life Technologies); termed complete media. Clonal HEK 293cell lines were maintained in complete media supplemented with 0.6 mg/mLG418 (Enzo Life Sciences).

Experiment 1 Identification of PDE4 Long Form Activators of the PresentInvention Using Full-Length Human PDE4 Isoforms PDE4D5, PDE4A4, PDE4B1and PDE4B2

(Marchmont, R. J. and Houslay, M. D. Biochem. J. 187: 381-92, 1980)

Cell Line Generation

HEK 293 cells were transfected with pDEST™ PDE4 expression vectors usingLipofectamine LTX/Plus reagent (Invitrogen) as outlined by themanufacturer and clonal isolates expanded to obtain cell lines thatstably expressed the full-length human PDE4D5, PDE4A4 and PDE4B1 longisoforms and the full length human PDE4B2 short isoform. These werecalled the HEK-PDE4D5, HEK-PDE4A4, HEK-PDE4B1 and HEK-PDE4B2 cell lines,respectively.

Lysate Preparation (Using PDE4D5 as a Typical Example)

HEK-PDE4D5 cells were seeded out in 100 mm plates and incubated at 37°C. in an atmosphere of 5% CO₂, 95% air. Cell lysates were prepared usingKHEM buffer [50 mM KCl, 10 mM EGTA, 50 mM HEPES (pH 7.2), 1.92 mMMgCl₂].

To prepare the cell lysates, the 100 mm plates containing the cells wereplaced on ice and washed with ice-cold PBS (phosphate buffered saline,pH 7.4). KHEM buffer (500 μl) was added to the cells. Cells were thenscraped off the plate and triturated using a needle (BD Microlance™ 0.8,40 mm). The lysed cells were then centrifuged at 2000 rpm for 10 minutesto remove cell debris and the supernatant (cell lysate containingrecombinant PDE4D5) was transferred to a fresh tube and kept on ice.

Cytosol Fraction Preparation (Using PDE4D5 as a Typical Example)

The cell lysate containing recombinant PDE4D5 was transferred into acentrifuge tube and placed into an ultracentrifuge (BECKMAN COULTER) andspun at high speed (100,000 g) for 30 minutes at 4° C. The cytosolfraction was then collected and its protein amount determined using aBCA protein assay.

PDE Assay (Using PDE4D5 as a Typical Example)

PDE assays were performed using a final concentration of 10 mM Tris/5 mMMgCl₂ and 1 μM [3H]-cAMP (Perkin Elmer) plus PDE4D5 cell lysate cytosolfraction, containing over-expressed PDE4D5, with and without testcompound. Incubations were performed at 30° C. for 5 minutes. Thesamples were then placed in a boiling water bath for 2 minutes todenature the PDE enzyme, and returned to ice. Samples were allowed tocool for 10 min after which snake venom 5′-nucleotidase (25 μl, 1 mg/ml;Sigma) was added. The tubes were vortexed and incubated in a water bathat 30° C. for 10 minutes, to attain conversion of [3H]-5′-AMP to[3H]-adenosine, and then placed on ice. Dowex ion exchange resin (Sigma)prepared as a 1:1 Dowex: water stock was thoroughly re-suspended anddiluted 2:1 with ethanol. The resulting Dowex suspension (0.4 ml) wasadded to each tube. Tubes were vortexed to mix and then incubated on icefor at least 15 minutes before a final vortex. The Dowex resin waspelleted by centrifugation at 13,000 g at 4° C. for 3 minutes and 150 μlof the supernatant was removed to an Eppendorf tube containing 1 ml ofScintiSafe3 scintillation fluid (Fisher). Tubes were vortexed thoroughlyto mix and the recovered [3H]-adenosine was quantified by measuringcounts over 1 minute in a scintillation counter.

Compounds of the present invention activated the PDE4 long forms PDE4D5,PDE4A4 and PDE4B1 in a concentration dependent manner. Under the sameassay conditions, compounds of the present invention did not activatethe PDE4 short form, PDE4B2.

Data are shown in graphical form in FIGS. 1 to 4.

Experiment 2 Reduction of Intracellular cAMP Levels in HEK 293 or MDCKCells by PDE4 Long Form Activators

HEK 293 or MDCK cells were seeded at 100,000 cells per well, and left toadhere overnight. The cells were then treated with the compoundindicated (10 μM) for 10 minutes, prior to stimulation with forskolin(10 μM, Sigma) for 2 minutes. Media was aspirated, and hydrochloric acid(0.1M) was added to lyse the cells. The cAMP assay (Enzo Life Sciences)was performed according to the manufacturer's instructions.

Compounds of the present invention reduced intracellular cAMP levels inforskolin stimulated HEK 293 or MDCK cells.

Data are shown in graphical form in FIGS. 5 and 6.

Experiment 3 Inhibition of In Vitro Cyst Formation in MDCK Cells Treatedwith PDE4 Long Form Activators

In this study, the well-established three-dimensional (3D) MDCK cellmodel was used to investigate the effects of PDE4 long form activatorson the formation of kidney cysts and evaluate their potential in thetreatment of polycystic kidney diseases. 3D cysts were generated basedon the method of Mao et al. (Mao, Z., Streets, A. J., Ong, A. C. M. Am.J. Physiol. Renal Physiol. 300(6): F1375-F1384, 2011), with somemodifications. MDCK cells (50,000 cells/well) were seeded into collagen(Life Technologies; final concentration 1 mg/mL), containing 17 mM NaOHin DMEM, supplemented with 2% (v/v) FBS, 2 mM L-glutamine and 2 mML-glutamine, 1,000 U penicillin and 1,000 μg streptomycin (DMEM-2% FBS),on ice. Upon gelling at 37° C., 1 mL of DMEM-2% FBS was added along withthe test compound indicated in the presence of 10 μM forskolin (Sigma)and 1 μg/mL [Arg⁸]-vasopressin acetate salt (Sigma). Media wasreplenished every 2 days for 20 days; at every feed, test compound,forskolin and vasopressin were added.

Phase-contrast images were obtained on the Motic microscope (×200magnification) every 2 days for 20 days. Per condition, 10 images weretaken (in duplicate) and the average cyst radius measured.

Compounds of the present invention inhibited in vitro cyst formation inthe MDCK cells in a concentration dependent manner.

The day 20 phase-contrast images and cyst radius graphs for Example Aare shown in FIG. 7.

Experiment 4 Reversal of In Vitro Cyst Formation in MDCK Cells Treatedwith PDE4 Long Form Activators

In this study, the potential of PDE4 long form activators to reverse theformation of pre-formed cysts was evaluated. The experiment was carriedout according to the method of Experiment 3. For the first 10 days,forskolin and vasopressin were added at every feed (every 2 days) but notest compound was added. For the next 10 days, the test compound,forskolin and vasopressin were added at every feed (every 2 days).

Phase-contrast images were obtained on the Motic microscope (×200magnification) every 2 days for 20 days. Per condition, 10 images weretaken (in duplicate) and the average cyst radius measured.

Compounds of the present invention reversed in vitro cyst formation inthe MDCK cells in a concentration dependent manner.

The day 20 phase-contrast images and cyst radius graphs for Example Aare shown in FIG. 8.

Experiment 5 Inhibition of Proliferation of LNCaP Human Prostate CancerCells

In this study, the potential utility of PDE4 long form activators in thetreatment of prostate cancer was studied using the LNCaP human prostatecancer cell line. The experiments were carried out according to themethod described by Henderson et al. (Henderson, D. J. P., Byrne, A.,Dulla, K., Jenster, G., Hoffmann, R., Baillie, G. S., Houslay, M. D. Br.J. Cancer 110: 1278-1287, 2014).

LNCaP Cell Culture

Androgen-sensitive (AS) LNCaP cells were maintained in RPM11640supplemented with 10% FBS (Seralabs), 2 mM L-glutamine and 1,000 Upenicillin-streptomycin. LNCaP androgen-insensitive (AI) cells weregenerated in-house by culturing the LNCaP-AS cells in RPM11640supplemented with 10% charcoal stripped FBS, 2 mM L-glutamine and 1,000U penicillin-streptomycin for a minimum of four weeks. All tissueculture reagents were from Life Technologies.

Xcelligence (Roche) Proliferation Assay

Cell proliferation is measured as a function of changing electricalimpedance. Values are represented by cell index number, a dimensionlessunit of measurement representing the cell status, which increases ascells adhere to 96-well electrode plates and divide.

LNCaP AI/AS cells were plated at a density of 25,000 cells per well in a96-well electrode plate (in triplicate), in the presence/absence ofvarious concentrations of test compound.

Cell indices were measured every 10 minutes for up to 100 hours,analysed using RICA software and normalised to the cell index ofvehicle-treated cells (n=3).

The effects of Example A on proliferation of androgen-sensitive (AS)LNCaP human prostate cancer cells are shown in FIG. 9.

The effects of Example A on proliferation of androgen-insensitive (AI)LNCaP human prostate cancer cells are shown in FIG. 10.

Experiment 6 Measurement of In Vitro Clearance of Example A Using HumanHepatocytes

Human hepatocyte stability is considered the gold standard method forevaluating the hepatic metabolism of drugs in vitro. The in vitroclearance of Example A was evaluated using cryopreserved humanhepatocytes according to the method of Lau et al. (Lau, Y. Y. et al.Drug Metab. Dispos. 30: 1446-1454, 2002) with minor modifications.

Cryopreserved hepatocytes were thawed in a water bath at 37° C. andtransferred to a tube containing 50 ml of hepatocyte thaw medium. Thehepatocytes were centrifuged at 500 rpm for 3 min. The supernatant wasremoved and the hepatocytes were resuspended in medium, mixed gently andcentrifuged again at 500 rpm for 3 min. The supernatant was discardedand the hepatocyte pellet was gently resuspended in medium to a finaldensity of 2 million cells/ml.

Incubations were carried out at a final test compound concentration of 1μM. Stock solutions of the compounds were prepared in DMSO and dilutedto the desired concentrations before adding to the hepatocytes.Incubations were carried out with a hepatocyte concentration of 1million cells/ml. Samples (100 μL) were incubated at 37° C. for 0, 15,30, 60 and 120 min in duplicate. At the end of the incubation time, 200μl of acetonitrile with internal standard was added and the wells weresealed.

The samples were sonicated for 2 min and centrifuged at 6000 rpm for 10min, and 50 μL of the supernatant was transferred into a 96-well platecontaining 50 μL of ultrapure water for LC-MS/MS analysis.

The samples were analysed by LC-MS/MS using a Sciex API4000™ system. Thehalf-life of Example A in this assay was 54 minutes, indicating thatExample A is moderately stable in human hepatocytes.

Experiment 7 Pharmacokinetic Profile of Example A in Male C57 Mice

Example A was dissolved in 5% DMA+10% Solutol+85%(10% HPBCD in water) toafford a clear dosing solution of 1 mg/mL. The dosing solution wasadministered to three mice at 2 mg/kg i.v. via the tail vein and tothree further mice at 10 mg/kg p.o. via oral gavage. Blood samples (ca.20 μL) were collected at 2, 5, 20 min, 1, 2, 4, 8 and 12 h after i.v.dosing and at 15, 30 min, 1, 2, 4, 8, 12 and 24 h after oral dosing. Theblood samples were diluted with 3 volumes of distilled water and storedat −80° C. until analysis. The samples were analysed by UPLC-MS/MS (API5500).

Example A exhibited 66% oral bioavailability in male C57 mice, with aterminal half life of 4.9 hours after oral dosing and 4.2 hours afteri.v. dosing. No abnormal effects were observed in the mice. The meanwhole blood concentration-time profiles of Example A after i.v. and p.o.dosing are shown in FIG. 11.

Experiment 8 Pharmacokinetic Profile of Example A in Male SD Rats

Example A was dissolved in 5% DMA+10% Solutol+85%(10% HPBCD in saline)to afford a clear dosing solution of 1 mg/mL. The dosing solution wasadministered to three rats at 2 mg/kg i.v. via the foot dorsal vein andto three further rats at 10 mg/kg p.o. via oral gavage. Blood samples(ca. 150 μL) were collected at 2, 5, 20 min, 1, 2, 4, 8, 12 and 24 hafter i.v. dosing and at 5, 15, 30 min, 1, 2, 4, 8, 12 and 24 h afteroral dosing. The blood samples were centrifuged at 4° C. (2000 g, 5 min)within 15 min of sample collection to obtain plasma samples. Plasmasamples were stored at −80° C. until analysis. The samples were analysedby UPLC-MS/MS (API 4000).

Example A exhibited 100% oral bioavailability in male SD rats, with aterminal half life of 9.1 hours after oral dosing and 2.2 hours afteri.v. dosing. No abnormal effects were observed in the rats. The meanplasma concentration-time profiles of Example A after i.v. and p.o.dosing are shown in FIG. 12.

Experiment 9 Inhibition of In Vitro Cyst Formation in OX161 CellsTreated with PDE4 Long Form Activators of the Present Invention

In this study, a human ADPKD patient-derived (OX161) cell line was usedto investigate the effects of PDE4 long form activators on the formationof kidney cysts in vitro and evaluate their potential in the treatmentof polycystic kidney diseases. Conditionally immortalised OX161 cystictubular epithelial cells were generated from human kidneys removed forclinical indications from ADPKD patients with characterised PKD1 (PC1)mutations (Parker, E., Newby, L. J., Sharpe, C. C., Rossetti, S.,Streets, A. J., Harris, P. C., O'Hare, M. J., Ong, A. C. M. Kidney Int.72(2): 157-165, 2007).

OX161 cells (50,000 cells/well) were seeded into collagen (LifeTechnologies; final concentration 1 mg/mL), containing 17 mM NaOH inDMEM, supplemented with 2% (v/v) FBS, 2 mM L-glutamine and 2 mML-glutamine, 1,000 U penicillin and 1,000 μg streptomycin (DMEM-2% FBS),on ice. Upon gelling at 37° C., 1 mL of DMEM-2% FBS was added along withthe test compound indicated in the presence of 10 μM forskolin. Mediawas replenished every 2 days for 10 days; at every feed, test compoundand forskolin were added.

Phase-contrast images were obtained every 2 days for 10 days. Percondition, 10 images were taken (in duplicate) and the average cyst areacalculated.

Example A inhibited in vitro cyst formation in the OX161 cells in aconcentration dependent manner.

The day 10 phase-contrast images and cyst area graphs for Example A areshown in FIG. 13 (Panel A).

Experiment 10 Reversal of In Vitro Cyst Formation in OX161 Cells Treatedwith PDE4 Long Form Activators of the Present Invention

In this study, the potential of PDE4 long form activators to reverse theformation of pre-formed cysts was evaluated in a human ADPKDpatient-derived OX161 cell line. The experiment was carried outaccording to the method of Experiment 9. For the first 10 days,forskolin was added at every feed (every 2 days) but no test compoundwas added. For the next 10 days, the test compound and forskolin wereadded at every feed (every 2 days).

Phase-contrast images were obtained every 2 days for 20 days. Percondition, 10 images were taken (in duplicate) and the average cyst areacalculated.

Example A reversed in vitro cyst formation in the OX161 cells in aconcentration dependent manner.

The day 20 phase-contrast images and cyst area graphs for Example A areshown in FIG. 13 (Panel B).

TABLE 1 Novel small molecule PDE4 long form activators of Formula 1 andFormula 2 (Examples A to L), according to the present inventionMolecular weight Compound Chemical name (Daltons) Chemical StructureExample A N-(3-Fluorobenzyl)-2-[3-(4- chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide 390.8

Example B N-Benzyl-2-[3-(4-chlorophenyl)- 5-methoxymethyl-1H-1,2,4-triazol-1-yl]acetamide 370.8

Example C N-Benzyl-2-[3-(4-chlorophenyl)- 5-methyl-1H-1,2,4-triazol-1-yl]acetamide 340.8

Example D N-(3-Fluorobenzyl)-2-{3-[4- (trifluoromethoxy)-phenyl]-5-methoxymethyl-1H-1,2,4-triazol- 1-yl}acetamide 438.4

Example E N-(3-Chlorobenzyl)-2-[3-(4- chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide 407.3

Example F N-(3-Cyanobenzyl)-2-[3-(4- chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide 397.8

Example G N-[3-(Trifluoromethyl)benzyl]-2-[3-(4-chloro-3-fluorophenyl)-5- ethyl-1H-1,2,4-triazol-1- yl]acetamide440.8

Example H N-(3-Methoxybenzyl)-2-[3-(4- chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide 402.8

Example I N-[3-(Trifluoromethoxy)benzyl]-2-[3-(4-chloro-3-fluorophenyl)-5- ethyl-1H-1,2,4-triazol-1- yl]acetamide456.8

Example J N-(2-Fluorobenzyl)-2-[3-(4- chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide 390.8

Example K N-(4-Fluorobenzyl)-2-[3-(4- chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide 390.8

Example L N-(3,4-Dimethoxybenzyl)-2-[3- (4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1- yl]acetamide 432.9

Using the method described in Experiment 1, the compounds shown in Table1 were identified as PDE4 long form activators.

TABLE 2 Activation of PDE4D5, a long form of PDE4, by Examples A to LUsing the method described in Experiment 1, the followingconcentration/PDE4D5 activity data were obtained for Examples A to L.Data are shown in graphical form in FIG. 1. Concentration PDE4D5Compound (μM) activity* SEM Example A 1 −3.6 6.7 Example A 3 −0.2 9.5Example A 10 12.5 13.4 Example A 30 39.7 15.7 Example A 50 91.9 13.1Example B 1 7.2 11.1 Example B 3 0.4 6.3 Example B 10 21.9 6.6 Example B30 64.6 24.9 Example B 50 113.8 13.7 Example C 50 118.7 24.1 Example D 152.6 27.2 Example D 3 30.6 9.0 Example D 10 51.6 13.2 Example D 30 126.232.2 Example D 50 196.3 58.1 Example E 50 71.1 12.9 Example F 50 107.341.7 Example G 50 171.1 6.4 Example H 50 136.4 40.3 Example I 50 92.17.8 Example J 50 82.2 17.9 Example K 50 80.5 8.5 Example L 1 26.0 13.8Example L 3 42.4 26.9 Example L 10 79.8 29.9 Example L 30 213.6 44.8Example L 50 250.9 56.2 *Measured as mean % increase in counts overbasal activity without added compound (n ≥ 2)

TABLE 3 Activation of PDE4A4, another long form of PDE4, by Example AUsing the method described in Experiment 1, the followingconcentration/PDE4A4 activity data were obtained for Example A. Data areshown in graphical form in FIG. 2. Concentration PDE4A4 Compound (μM)activity* SEM Example A 1 1.1 8.8 Example A 3 2.7 1.3 Example A 10 10.45.2 Example A 30 38.5 8.7 Example A 50 65.4 25.0 *Measured as mean %increase in counts over basal activity without added compound (n ≥ 2)

TABLE 4 Activation of PDE4B1, another long form of PDE4, by Example AUsing the method described in Experiment 1, the followingconcentration/PDE4B1 activity data were obtained for Example A. Data areshown in graphical form in FIG. 3. Concentration PDE4B1 Compound (μM)activity* SEM Example A 1 −2.4 3.4 Example A 3 4.9 6.3 Example A 10 22.05.1 Example A 30 61.3 5.8 Example A 50 92.9 7.5 *Measured as mean %increase in counts over basal activity without added compound (n ≥ 2)

The invention claimed is:
 1. A compound of Formula 1:

wherein R¹ is selected from H, (C1-4)alkyl and (C1-4)alkyloxy, the(C1-4)alkyl and (C1-4)alkyloxy groups being optionally substituted with1 to 3 fluoros; R² and R⁶ are independently selected from H,(C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the (C1-4)alkyl and(C1-4)alkyloxy groups being optionally substituted with 1 to 3 fluoros;R³, R⁴ and R⁵ are independently selected from H, (C1-4)alkyl,(C1-4)alkyloxy, (C1-4)alkylsulfonyl, C(O)—NR¹⁶R¹⁷, C(O)—OR¹⁶,S(O)₂—NR¹⁶R¹⁷, CN and halogen, the (C1-4)alkyl and (C1-4)alkyloxy groupsbeing optionally substituted with 1 to 3 fluoros; R⁷, R⁸, R¹⁰ and R¹¹are independently selected from H and F; R⁹ is selected from H,(C1-4)alkyl, (C1-4)alkyloxy, (C1-4)alkylsulfonyl, C(O)—NR¹⁶R¹⁷,C(O)—OR¹⁶, S(O)₂—NR¹⁶R¹⁷, CN and halogen, the (C1-4)alkyl and(C1-4)alkyloxy groups being optionally substituted with 1 to 3 fluoros;R¹², R¹³, R¹⁴ and R¹⁵ are independently selected from H and (C1-4)alkyl;each R¹⁶ and R¹⁷, when present, is independently selected from H and(C1-4)alkyl; or a pharmaceutically acceptable salt thereof.
 2. Thecompound or pharmaceutically acceptable salt of claim 1, wherein R⁷ andR¹¹ are H and/or wherein R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are H.
 3. Thecompound or pharmaceutically acceptable salt of claim 1, wherein R⁹ isselected from (C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the(C1-4)alkyl and (C1-4)alkyloxy groups being optionally substituted with1 to 3 fluoros.
 4. The compound or pharmaceutically acceptable salt ofclaim 1, wherein R⁷, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are H, and R⁹ isselected from (C1-4)alkyl, (C1-4)alkyloxy, CN and halogen, the(C1-4)alkyl and (C1-4)alkyloxy groups being optionally substituted with1 to 3 fluoros.
 5. The compound or pharmaceutically acceptable salt ofclaim 1, wherein R¹ is selected from H, methyl, and methoxy.
 6. Thecompound or pharmaceutically acceptable salt of claim 1 wherein R² andR⁶ are each independently selected from H and halogen.
 7. The compoundor pharmaceutically acceptable salt of claim 1 wherein R³, R⁴ and R⁵ areeach independently selected from H, halogen, CN, (C1-4)alkyl and(C1-4)alkyloxy, the (C1-4)alkyl and (C1-4)alkyloxy groups beingoptionally substituted with 1 to 3 fluoros.
 8. The compound orpharmaceutically acceptable salt of claim 1 wherein R⁴ is selected fromH, fluoro and methoxy.
 9. The compound or pharmaceutically acceptablesalt of claim 1 wherein R⁹ is selected from methyl, chloro andtrifluoromethoxy.
 10. The compound or pharmaceutically acceptable saltof claim 1 wherein: a. one of R⁸ and R¹⁰ is H and the other is fluoro;b. R⁸ and R¹⁰ are both H; or c. R⁹ is chloro, one of R⁸ and R¹⁰ is H andthe other of R⁸ and R¹⁰ is fluoro.
 11. The compound of claim 1 selectedfromN-(3-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-Benzyl-2-[3-(4-chlorophenyl)-5-methoxymethyl-1H-1,2,4-triazol-1-yl]acetamide;N-Benzyl-2-[3-(4-chlorophenyl)-5-methyl-1H-1,2,4-triazol-1-yl]acetamide;N-(3-Fluorobenzyl)-2-{3-[4-(trifluoromethoxy)-phenyl]-5-methoxymethyl-1H-1,2,4-triazol-1-yl}acetamide;N-(3-Chlorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-(3-Cyanobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-[3-(Trifluoromethyl)benzyl]-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-(3-Methoxybenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-[3-(Trifluoromethoxy)benzyl]-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-(2-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-(4-Fluorobenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;N-(3,4-Dimethoxybenzyl)-2-[3-(4-chloro-3-fluorophenyl)-5-ethyl-1H-1,2,4-triazol-1-yl]acetamide;and pharmaceutically acceptable salts thereof.
 12. A pharmaceuticalcomposition comprising a compound of claim 1, or a pharmaceuticallyacceptable salt thereof, and a pharmaceutically acceptable excipient.13. A method of preparing a compound of Formula 1 as defined in claim 1or a pharmaceutically acceptable salt thereof, comprising the step ofreacting a compound of Formula 1A

with a compound of Formula 1B

wherein R¹-R¹⁵ are defined in claim
 1. 14. A method of preparing acompound of Formula 1 as defined in claim 1 or a pharmaceuticallyacceptable salt thereof, comprising the step of reacting a compound ofFormula 1C

with a compound of Formula 1D

wherein R¹-R¹⁵ are defined in claim 1.